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14469Mead, A. J.: Spherical collapse, formation hysteresis and the deeply non-linear cosmological power spectrum
http://adsabs.harvard.edu/abs/2017MNRAS.464.1282M
I examine differences in non-linear structure formation between
cosmological models that share a z = 0 linear power spectrum in both
shape and amplitude, but that differ via their growth history. N-body
simulations of these models display an approximately identical
large-scale-structure skeleton, but reveal deeply non-linear differences
in the demographics and properties of haloes. I investigate to what
extent the spherical-collapse model can help in understanding these
differences, in both real and redshift space. I discuss how this is
difficult to do if one attempts to identify haloes directly, because in
that case one is subject to the vagaries of halo-finding algorithms.
However, I demonstrate that the halo model of structure formation
provides an accurate non-linear response in the power spectrum, but only
if results from spherical collapse that include formation hysteresis are
properly incorporated. I comment on how this fact can be used to provide
per cent level accurate matter power-spectrum predictions for dark
energy models for k ≤ 5 h Mpc<SUP>-1</SUP> by using the halo model as
a correction to accurate ΛCDM simulations. In the Appendix, I
provide some fitting functions for the linear-collapse threshold
(δ<SUB>c</SUB>) and virialized overdensity (Δ<SUB>v</SUB>)
that are valid for a wide range of dark energy models. I also make my
spherical-collapse code available at
https://github.com/alexander-mead/collapse.Su, T.: On the redshift distribution and physical properties of ACT-selected DSFGs
http://adsabs.harvard.edu/abs/2017MNRAS.464..968S
We present multi-wavelength detections of nine candidate gravitationally
lensed dusty star-forming galaxies (DSFGs) selected at 218 GHz (1.4 mm)
from the Atacama Cosmology Telescope (ACT) equatorial survey. Among the
brightest ACT sources, these represent the subset of the total ACT
sample lying in Herschel SPIRE fields, and all nine of the 218 GHz
detections were found to have bright Herschel counterparts. By fitting
their spectral energy distributions (SEDs) with a modified blackbody
model with power-law temperature distribution, we find the sample has a
median redshift of z=4.1^{+1.1}_{-1.0} (68 per cent confidence
interval), as expected for 218 GHz selection, and an apparent total
infrared luminosity of log _{10}(μ L_IR/L_{odot }) =
13.86^{+0.33}_{-0.30}, which suggests that they are either strongly
lensed sources or unresolved collections of unlensed DSFGs. The
effective apparent diameter of the sample is sqrt{μ }d=
4.2^{+1.7}_{-1.0} kpc, further evidence of strong lensing or
multiplicity, since the typical diameter of DSFGs is 1.0-2.5 kpc. We
emphasize that the effective apparent diameter derives from SED
modelling without the assumption of optically thin dust (as opposed to
image morphology). We find that the sources have substantial optical
depth (tau = 4.2^{+3.7}_{-1.9}) to dust around the peak in the modified
blackbody spectrum (λ<SUB>obs</SUB> ≤ 500 μm), a result
that is robust to model choice.Blagrave, K.: DHIGLS: DRAO H i Intermediate Galactic Latitude Survey
http://adsabs.harvard.edu/abs/2017ApJ...834..126B
Observations of Galactic H i gas for seven targeted regions at
intermediate Galactic latitude are presented at 1<SUP>\prime</SUP>
angular resolution using data from the DRAO Synthesis Telescope (ST) and
the Green Bank Telescope (GBT). The DHIGLS data are the most extensive
arcminute-resolution measurements of the diffuse atomic interstellar
medium beyond those in the Galactic plane. The acquisition, reduction,
calibration, and mosaicking of the DRAO ST data and the cross
calibration and incorporation of the short-spacing information from the
GBT are described. The high quality of the resulting DHIGLS products
enables a variety of new studies in directions of low Galactic column
density. We analyze the angular power spectra of maps of the integrated
H i emission (column density) from the data cubes for several distinct
velocity ranges. In fitting power-spectrum models based on a power law,
but including the effects of the synthesized beam and noise at high
spatial frequencies, we find exponents ranging from ‑2.5 to
‑3.0. Power spectra of maps of the centroid velocity for these
components give similar results. These exponents are interpreted as
being representative of the three-dimensional density and velocity
fields of the atomic gas, respectively. We find evidence for dramatic
changes in the H i structures in channel maps over even small changes in
velocity. This narrow line emission has counterparts in absorption
spectra against bright background radio sources, quantifying that the
gas is cold and dense and can be identified as the cold neutral medium
phase. Fully reduced DHIGLS H i data cubes and other data products are
available at <A
href="http://www.cita.utoronto.ca/DHIGLS">www.cita.utoronto.ca/DHIGLS</A>.Petrovich, C.: Planetary Engulfment as a Trigger for White Dwarf Pollution
http://adsabs.harvard.edu/abs/2017ApJ...834..116P
The presence of a planetary system can shield a planetesimal disk from
the secular gravitational perturbations due to distant outer massive
objects (planets or stellar companions). As the host star evolves off
the main sequence to become a white dwarf, these planets can be engulfed
during the giant phase, triggering secular instabilities and leading to
the tidal disruptions of small rocky bodies. These disrupted bodies can
feed the white dwarfs with rocky material and possibly explain the
high-metallicity material in their atmospheres. We illustrate how this
mechanism can operate when the gravitational perturbations are due to
the KL mechanism from a stellar binary companion, a process that is
activated only after the planet has been removed/engulfed. We show that
this mechanism can explain the observed accretion rates if: (1) the
planetary engulfment happens rapidly compared to the secular timescale,
which is generally the case for wide binaries (> 100 au) and
planetary engulfment during the asymptotic giant branch; (2) the
planetesimal disk has a total mass of ∼
{10}<SUP>-4</SUP>-{10}<SUP>-2</SUP>{M}<SUB>\oplus </SUB>. We show that
this new mechanism can provide a steady supply of material throughout
the entire life of the white dwarfs for all cooling ages and can account
for a large fraction (up to nearly half) of the observed polluted white
dwarfs.Miville-Deschênes, M.-A.: Physical Properties of Molecular Clouds for the Entire Milky Way Disk
http://adsabs.harvard.edu/abs/2017ApJ...834...57M
This study presents a catalog of 8107 molecular clouds that covers the
entire Galactic plane and includes 98% of the <SUP>12</SUP>CO emission
observed within b+/- 5^\circ . The catalog was produced using a
hierarchical cluster identification method applied to the result of a
Gaussian decomposition of the Dame et al. data. The total H<SUB>2</SUB>
mass in the catalog is 1.2× {10}<SUP>9</SUP> {M}<SUB>ȯ
</SUB>, in agreement with previous estimates. We find that 30% of the
sight lines intersect only a single cloud, with another 25% intersecting
only two clouds. The most probable cloud size is R∼ 30 pc. We find
that M\propto {R}<SUP>2.2+/- 0.2</SUP>, with no correlation between the
cloud surface density, Σ, and R. In contrast with the general
idea, we find a rather large range of values of Σ, from 2 to 300 M
<SUB>⊙</SUB> pc<SUP>‑2</SUP>, and a systematic decrease with
increasing Galactic radius, {R}<SUB>{gal</SUB>}. The cloud velocity
dispersion and the normalization {σ }<SUB>0</SUB>={σ
}<SUB>v</SUB>/{R}<SUP>1/2</SUP> both decrease systematically with
{R}<SUB>{gal</SUB>}. When studied over the whole Galactic disk, there is
a large dispersion in the line width–size relation and a
significantly better correlation between {σ }<SUB>v</SUB> and
{{Σ }} R. The normalization of this correlation is constant to
better than a factor of two for {R}<SUB>{gal</SUB>}< 20 {kpc}. This
relation is used to disentangle the ambiguity between near and far
kinematic distances. We report a strong variation of the turbulent
energy injection rate. In the outer Galaxy it may be maintained by
accretion through the disk and/or onto the clouds, but neither source
can drive the 100 times higher cloud-averaged injection rate in the
inner Galaxy.Hopkins, P. F.: Feedback: Now with Physics
http://adsabs.harvard.edu/abs/2017AAS...22933101H
The most fundamental unsolved problems in galaxy formation revolve
around "feedback" from massive stars and black holes. In the last few
years, a new generation of theoretical models have emerged which combine
new numerical methods and physics in an attempt to realistically model
the diverse physics of the interstellar medium, star formation, and
feedback from super-massive black holes and massive stars (winds, jets,
SNe, and radiation). These mechanisms lead to 'self-regulated' galaxy
and star formation, in which global correlations such as the
Schmidt-Kennicutt law, the inefficiency of star formation, and the
stellar mass function -- emerge naturally. Within galaxies, feedback
regulates the structure of the interstellar medium, and many observed
properties of the ISM, star formation, and galaxies can be understood as
a fundamental consequence of super-sonic turbulence in a rapidly
cooling, self-gravitating medium. But feedback also produces galactic
super-winds that can dramatically alter the cosmological evolution of
galaxies, change the nature of dark matter cores and
‘cusps’, and re-structure the circum-galactic and
inter-galactic medium. These winds depend non-linearly on multiple
feedback mechanisms in a way that explains why they have been so
difficult to model in previous "sub-grid" approaches. This resolves
long-standing problems in understanding even apparently "simple" galaxy
properties like the mass-metallicity relation. Finally, I'll discuss
where feedback fails, and where either additional, exotic physics, or
new, previously-dismissed feedback mechanisms, may be needed to explain
observations.Fissel, L. M.: BLAST-TNG: A Next Generation Balloon-borne Large Aperture Submillimeter Polarimeter
http://adsabs.harvard.edu/abs/2017AAS...22913306F
Measurements of polarized thermal dust emission can be used to map
magnetic fields in the interstellar medium. Recently, BLASTPol, the
Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry,
has published the most detailed map ever made of a giant molecular cloud
forming high-mass stars. I will present an overview of The Next
Generation BLAST polarimeter (BLAST-TNG), the successor telescope to
BLASTPol, which maps linearly polarized dust emission at 250, 350 and
500 μm. BLAST-TNG utilizes a 2.5-meter carbon-fiber primary mirror
that illuminates focal plane arrays containing over 3,000 microwave
kinetic inductance detectors. This new polarimeter has an order of
magnitude increase in mapping speed and resolution compared to BLASTPol
and we expect to make over 500,000 measurements of magnetic field
orientation per flight. BLAST-TNG will have the sensitivity to map
entire molecular cloud complexes as well as regions of diffuse high
Galactic latitude dust. It also has the resolution (FWHM =
25’’ at 250 μm) necessary to trace magnetic fields in
prestellar cores and dense filaments. BLAST-TNG will thus provide a
crucial link between the low resolution Planck all-sky maps and the
detailed but narrow field of view polarimetry capabilities of ALMA. For
our first Antarctic flight in December 2017 we are putting out a call
for shared-risk proposals to fill 25% of the available science time. In
addition, BLAST-TNG data will be publicly released within a year of the
publication of our first look papers, leaving a large legacy data set
for the study of the role played by magnetic fields in the star
formation process and the properties of interstellar dust.Abbott, B. P.: Prospects for Observing and Localizing Gravitational-Wave Transients with Advanced LIGO and Advanced Virgo
http://adsabs.harvard.edu/abs/2016LRR....19....1A
We present a possible observing scenario for the Advanced LIGO and
Advanced Virgo gravitational-wave detectors over the next decade, with
the intention of providing information to the astronomy community to
facilitate planning for multi-messenger astronomy with gravitational
waves. We determine the expected sensitivity of the network to transient
gravitational-wave signals, and study the capability of the network to
determine the sky location of the source. We report our findings for
gravitational-wave transients, with particular focus on
gravitational-wave signals from the inspiral of binary neutron-star
systems, which are considered the most promising for multi-messenger
astronomy. The ability to localize the sources of the detected signals
depends on the geographical distribution of the detectors and their
relative sensitivity, and 90% credible regions can be as large as
thousands of square degrees when only two sensitive detectors are
operational. Determining the sky position of a significant fraction of
detected signals to areas of 5 deg<SUP>2</SUP> to 20 deg<SUP>2</SUP>
will require at least three detectors of sensitivity within a factor of
˜ 2 of each other and with a broad frequency bandwidth. Should the
third LIGO detector be relocated to India as expected, a significant
fraction of gravitational-wave signals will be localized to a few square
degrees by gravitational-wave observations alone.Lovelace, G.: Modeling the source of GW150914 with targeted numerical-relativity simulations
http://adsabs.harvard.edu/abs/2016CQGra..33x4002L
In fall of 2015, the two LIGO detectors measured the gravitational wave
signal GW150914, which originated from a pair of merging black holes
(Abbott et al Virgo, LIGO Scientific 2016 Phys. Rev. Lett. <A href="http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102">116</A>
<A href="http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102">061102</A>).
In the final 0.2 s (about 8 gravitational-wave cycles) before the
amplitude reached its maximum, the observed signal swept up in amplitude
and frequency, from 35 Hz to 150 Hz. The theoretical gravitational-wave
signal for merging black holes, as predicted by general relativity, can
be computed only by full numerical relativity, because analytic
approximations fail near the time of merger. Moreover, the nearly-equal
masses, moderate spins, and small number of orbits of GW150914 are
especially straightforward and efficient to simulate with modern
numerical-relativity codes. In this paper, we report the modeling of
GW150914 with numerical-relativity simulations, using black-hole masses
and spins consistent with those inferred from LIGO’s measurement
(Abbott et al LIGO Scientific Collaboration, Virgo Collaboration 2016
Phys. Rev. Lett. <A href="http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241102">116</A>
<A href="http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241102">241102</A>).
In particular, we employ two independent numerical-relativity codes that
use completely different analytical and numerical methods to model the
same merging black holes and to compute the emitted gravitational
waveform; we find excellent agreement between the waveforms produced by
the two independent codes. These results demonstrate the validity,
impact, and potential of current and future studies using
rapid-response, targeted numerical-relativity simulations for better
understanding gravitational-wave observations.Thornton, R. J.: The Atacama Cosmology Telescope: The Polarization-sensitive ACTPol Instrument
http://adsabs.harvard.edu/abs/2016ApJS..227...21T
The Atacama Cosmology Telescope (ACT) makes high angular resolution
measurements of anisotropies in the Cosmic Microwave Background (CMB) at
millimeter wavelengths. We describe ACTPol, an upgraded receiver for
ACT, which uses feedhorn-coupled, polarization-sensitive detector
arrays, a 3° field of view, 100 mK cryogenics with continuous
cooling, and meta material antireflection coatings. ACTPol comprises
three arrays with separate cryogenic optics: two arrays at a central
frequency of 148 GHz and one array operating simultaneously at both 97
GHz and 148 GHz. The combined instrument sensitivity, angular
resolution, and sky coverage are optimized for measuring angular power
spectra, clusters via the thermal Sunyaev-Zel’dovich (SZ)
and kinetic SZ signals, and CMB lensing due to large-scale structure.
The receiver was commissioned with its first 148 GHz array in 2013,
observed with both 148 GHz arrays in 2014, and has recently completed
its first full season of operations with the full suite of three arrays.
This paper provides an overview of the design and initial performance of
the receiver and related systems.Abbott, B. P.: Supplement: “The Rate of Binary Black Hole Mergers Inferred from Advanced LIGO Observations Surrounding GW150914” (2016, ApJL, 833, L1)
http://adsabs.harvard.edu/abs/2016ApJS..227...14A
This article provides supplemental information for a Letter reporting
the rate of (BBH) coalescences inferred from 16 days of coincident
Advanced LIGO observations surrounding the transient (GW) signal
GW150914. In that work we reported various rate estimates whose 90%
confidence intervals fell in the range 2-600
Gpc<SUP>-3</SUP> yr<SUP>-1</SUP>. Here we give details on
our method and computations, including information about our search
pipelines, a derivation of our likelihood function for the analysis, a
description of the astrophysical search trigger distribution expected
from merging BBHs, details on our computational methods, a description
of the effects and our model for calibration uncertainty, and an
analytic method for estimating our detector sensitivity, which is
calibrated to our measurements.Abbott, B. P.: The Rate of Binary Black Hole Mergers Inferred from Advanced LIGO Observations Surrounding GW150914
http://adsabs.harvard.edu/abs/2016ApJ...833L...1A
A transient gravitational-wave signal, GW150914, was identified in the
twin Advanced LIGO detectors on 2015 September 2015 at 09:50:45 UTC. To
assess the implications of this discovery, the detectors remained in
operation with unchanged configurations over a period of 39 days around
the time of the signal. At the detection statistic threshold
corresponding to that observed for GW150914, our search of the 16 days
of simultaneous two-detector observational data is estimated to have a
false-alarm rate (FAR) of \lt 4.9× {10}<SUP>-6</SUP>
{{yr}}<SUP>-1</SUP>, yielding a p-value for GW150914 of \lt 2×
{10}<SUP>-7</SUP>. Parameter estimation follow-up on this trigger
identifies its source as a binary black hole (BBH) merger with component
masses
({m}<SUB>1</SUB>,{m}<SUB>2</SUB>)=({36}<SUB>-4</SUB><SUP>+5</SUP>,{29}<SUB>-4</SUB><SUP>+4</SUP>)
{M}<SUB>⊙ </SUB> at redshift
z={0.09}<SUB>-0.04</SUB><SUP>+0.03</SUP> (median and 90% credible
range). Here, we report on the constraints these observations place on
the rate of BBH coalescences. Considering only GW150914, assuming that
all BBHs in the universe have the same masses and spins as this event,
imposing a search FAR threshold of 1 per 100 years, and assuming that
the BBH merger rate is constant in the comoving frame, we infer a 90%
credible range of merger rates between 2{--}53 {{Gpc}}<SUP>-3</SUP>
{{yr}}<SUP>-1</SUP> (comoving frame). Incorporating all search triggers
that pass a much lower threshold while accounting for the uncertainty in
the astrophysical origin of each trigger, we estimate a higher rate,
ranging from 13{--}600 {{Gpc}}<SUP>-3</SUP> {{yr}}<SUP>-1</SUP>
depending on assumptions about the BBH mass distribution. All together,
our various rate estimates fall in the conservative range 2{--}600
{{Gpc}}<SUP>-3</SUP> {{yr}}<SUP>-1</SUP>.Liao, Y.-W.: Accurate Polarization Calibration at 800 MHz with the Green Bank Telescope
http://adsabs.harvard.edu/abs/2016ApJ...833..289L
Polarization leakage of foreground synchrotron emission is a critical
issue in H i intensity mapping experiments. While the sought-after H i
emission is unpolarized, polarized foregrounds such as Galactic and
extragalactic synchrotron radiation, if coupled with instrumental
impurity, can mimic or overwhelm the H i signals. In this paper, we
present the methodology for polarization calibration at 700-900
MHz, applied on data obtained from the Green Bank Telescope (GBT). We
use astrophysical sources, both polarized and unpolarized sources
including quasars and pulsars, as calibrators to characterize the
polarization leakage and control systematic effects in our GBT H i
intensity mapping project. The resulting fractional errors on
polarization measurements on boresight are well controlled to within
0.6%-0.8% of their total intensity. The polarized beam patterns
are measured by performing spider scans across both polarized quasars
and pulsars. A dominant Stokes I to V leakage feature and secondary
features of Stokes I to Q and I to U leakages in the 700-900 MHz
frequency range are identified. These characterizations are important
for separating foreground polarization leakage from the H i 21 cm
signal.Lee, E. J.: Observational Evidence of Dynamic Star Formation Rate in Milky Way Giant Molecular Clouds
http://adsabs.harvard.edu/abs/2016ApJ...833..229L
Star formation on galactic scales is known to be a slow process, but
whether it is slow on smaller scales is uncertain. We cross-correlate
5469 giant molecular clouds (GMCs) from a new all-sky catalog with 256
star-forming complexes (SFCs) to build a sample of 191 SFC-GMC
complexes—collections of multiple clouds each matched to 191 SFCs.
The total mass in stars harbored by these clouds is inferred from WMAP
free-free fluxes. We measure the GMC mass, the virial parameter,
the star formation efficiency ɛ and the star formation rate per
freefall time ɛ <SUB>ff</SUB>. Both ɛ and ɛ
<SUB>ff</SUB> range over 3-4 orders of magnitude. We find that
68.3% of the clouds fall within {σ }<SUB>{log</SUB>ɛ
}=0.79+/- 0.22 {dex} and {σ }<SUB>{log</SUB>{ɛ
}<SUB>{ff</SUB>}}=0.91+/- 0.22 {dex} about the median. Compared to these
observed scatters, a simple model with a time-independent ɛ
<SUB>ff</SUB> that depends on the host GMC properties predicts {σ
}<SUB>{log</SUB>{ɛ }<SUB>{ff</SUB>}}=0.12{--}0.24. Allowing for a
time-variable ɛ <SUB>ff</SUB>, we can recover the large
dispersion in the rate of star formation. This strongly suggests that
star formation in the Milky Way is a dynamic process on GMC scales. We
also show that the surface star formation rate profile of the Milky Way
correlates well with the molecular gas surface density profile.Merritt, A.: The Dragonfly Nearby Galaxies Survey. II. Ultra-Diffuse Galaxies near the Elliptical Galaxy NGC 5485
http://adsabs.harvard.edu/abs/2016ApJ...833..168M
We present the unexpected discovery of four ultra-diffuse galaxies
(UDGs) in a group environment. We recently identified seven extremely
low surface brightness galaxies in the vicinity of the spiral galaxy
M101, using data from the Dragonfly Telephoto Array. The galaxies have
effective radii of 10″-38″ and central surface
brightnesses of 25.6-27.7 mag arcsec<SUP>-2</SUP> in the
g-band. We subsequently obtained follow-up observations with HST to
constrain the distances to these galaxies. Four remain persistently
unresolved even with the spatial resolution of HST/ACS, which implies
distances of D\gt 17.5 Mpc. We show that the galaxies are most likely
associated with a background group at ˜27 Mpc containing the massive
ellipticals NGC 5485 and NGC 5473. At this distance, the galaxies have
sizes of 2.6-4.9 kpc, and are classified as UDGs, similar to the
populations that have been revealed in clusters such as Coma, Virgo, and
Fornax, yet even more diffuse. The discovery of four UDGs in a galaxy
group demonstrates that the UDG phenomenon is not exclusive to cluster
environments. Furthermore, their morphologies seem less regular than
those of the cluster populations, which may suggest a different
formation mechanism or be indicative of a threshold in surface density
below which UDGs are unable to maintain stability.Nguyễn-Lu'o'ng, Q.: The Scaling Relations and Star Formation Laws of Mini-starburst Complexes
http://adsabs.harvard.edu/abs/2016ApJ...833...23N
The scaling relations and star formation laws for molecular cloud
complexes (MCCs) in the Milky Way are investigated. MCCs are mostly
large (R > 50 pc), massive (˜106 {\text{}}{M}<SUB>⊙ </SUB>)
gravitationally unbound cloud structures. We compare their masses
{M}<SUB>{gas</SUB>}, mass surface densities {{{Σ
}}}<SUB>{M</SUB><SUB>{gas</SUB>}}, radii R, velocity dispersions
σ, star formation rates (SFRs), and SFR densities {{{Σ
}}}<SUB>{SFR</SUB>} with those of structures ranging from cores, clumps,
and giant molecular clouds, to MCCs, and galaxies, spanning eight orders
of magnitudes in size and 13 orders of magnitudes in mass. This results
in the following universal relations:σ ˜
{R}<SUP>0.5</SUP>,{M}<SUB>{gas</SUB>}˜ {R}<SUP>2</SUP>,{{{Σ
}}}<SUB>{SFR</SUB>}˜ {{{Σ
}}}<SUB>{M</SUB><SUB>{gas</SUB>}}<SUP>1.5</SUP>, {SFR}˜
{{M}<SUB>{gas</SUB>}}<SUP>0.9</SUP>, {and} {SFR}˜ {σ
}<SUP>2.7</SUP>. Variations in the slopes and coefficients of these
relations are found at individual scales, signifying different physics
acting at different scales. Additionally, there are breaks at the MCC
scale in the σ {--}R relation and between starburst and normal
star-forming objects in the {SFR}{--}{M}<SUB>{gas</SUB>} and {{{Σ
}}}<SUB>{SFR</SUB>}-{{{Σ
}}}<SUB>{{{M</SUB>}}<SUB>{gas</SUB>}} relations. Therefore, we propose
to use the Schmidt-Kennicutt diagram to distinguish starburst from
normal star-forming structures by applying a {{{Σ
}}}<SUB>{M</SUB><SUB>{gas</SUB>}} threshold of ˜100
{\text{}}{M}<SUB>⊙ </SUB> pc<SUP>-2</SUP> and a {{{Σ
}}}<SUB>{SFR</SUB>} threshold of 1 {\text{}}{M}<SUB>⊙ </SUB>
yr<SUP>-1</SUP> kpc<SUP>-2</SUP>. Mini-starburst complexes
are gravitationally unbound MCCs that have enhanced {{{Σ
}}}<SUB>{SFR</SUB>} (>1 {\text{}}{M}<SUB>⊙ </SUB>
yr<SUP>-1</SUP> kpc<SUP>-2</SUP>), probably caused by
dynamic events such as radiation pressure, colliding flows, or spiral
arm gravitational instability. Because of dynamical evolution,
gravitational boundedness does not play a significant role in regulating
the star formation activity of MCCs, especially the mini-starburst
complexes, which leads to the dynamical formation of massive stars and
clusters. We emphasize the importance of understanding mini-starbursts
in investigating the physics of starburst galaxies.Tamayo, D.: A Machine Learns to Predict the Stability of Tightly Packed Planetary Systems
http://adsabs.harvard.edu/abs/2016ApJ...832L..22T
The requirement that planetary systems be dynamically stable is often
used to vet new discoveries or set limits on unconstrained masses or
orbital elements. This is typically carried out via computationally
expensive N-body simulations. We show that characterizing the
complicated and multi-dimensional stability boundary of tightly packed
systems is amenable to machine-learning methods. We find that training
an XGBoost machine-learning algorithm on physically motivated features
yields an accurate classifier of stability in packed systems. On the
stability timescale investigated (10<SUP>7</SUP> orbits), it is three
orders of magnitude faster than direct N-body simulations. Optimized
machine-learning classifiers for dynamical stability may thus prove
useful across the discipline, e.g., to characterize the exoplanet sample
discovered by the upcoming Transiting Exoplanet Survey Satellite. This
proof of concept motivates investing computational resources to train
algorithms capable of predicting stability over longer timescales and
over broader regions of phase space.Abbott, B. P.: Upper Limits on the Rates of Binary Neutron Star and Neutron Star-Black Hole Mergers from Advanced LIGO’s First Observing Run
http://adsabs.harvard.edu/abs/2016ApJ...832L..21A
We report here the non-detection of gravitational waves from the merger
of binary-neutron star systems and neutron star-black hole
systems during the first observing run of the Advanced Laser
Interferometer Gravitational-wave Observatory (LIGO). In particular, we
searched for gravitational-wave signals from binary-neutron star
systems with component masses \in [1,3] {M}<SUB>⊙ </SUB> and
component dimensionless spins <0.05. We also searched for neutron
star-black hole systems with the same neutron star parameters,
black hole mass \in [2,99] {M}<SUB>⊙ </SUB>, and no restriction on
the black hole spin magnitude. We assess the sensitivity of the two LIGO
detectors to these systems and find that they could have detected the
merger of binary-neutron star systems with component mass
distributions of 1.35 ± 0.13 M <SUB>⊙</SUB> at a
volume-weighted average distance of ˜70 Mpc, and for neutron
star-black hole systems with neutron star masses of 1.4 M
<SUB>⊙</SUB> and black hole masses of at least 5 M <SUB>⊙</SUB>,
a volume-weighted average distance of at least ˜110 Mpc. From this
we constrain with 90% confidence the merger rate to be less than 12,600
Gpc<SUP>-3</SUP> yr<SUP>-1</SUP> for binary-neutron
star systems and less than 3600 Gpc<SUP>-3</SUP>
yr<SUP>-1</SUP> for neutron star-black hole systems. We
discuss the astrophysical implications of these results, which we find
to be in conflict with only the most optimistic predictions. However, we
find that if no detection of neutron star-binary mergers is made
in the next two Advanced LIGO and Advanced Virgo observing runs we would
place significant constraints on the merger rates. Finally, assuming a
rate of {10}<SUB>-7</SUB><SUP>+20</SUP> Gpc<SUP>-3</SUP>
yr<SUP>-1</SUP>, short gamma-ray bursts beamed toward the Earth,
and assuming that all short gamma-ray bursts have binary-neutron
star (neutron star-black hole) progenitors, we can use our 90%
confidence rate upper limits to constrain the beaming angle of the
gamma-ray burst to be greater than 2\buildrel{\circ}\over{.}
{3}<SUB>-1.1</SUB><SUP>+1.7</SUP> (4\buildrel{\circ}\over{.}
{3}<SUB>-1.9</SUB><SUP>+3.1</SUP>).Kostov, V. B.: Tatooine’s Future: The Eccentric Response of Kepler’s Circumbinary Planets to Common-envelope Evolution of Their Host Stars
http://adsabs.harvard.edu/abs/2016ApJ...832..183K
Inspired by the recent Kepler discoveries of circumbinary planets
orbiting nine close binary stars, we explore the fate of the former as
the latter evolve off the main sequence. We combine binary star
evolution models with dynamical simulations to study the orbital
evolution of these planets as their hosts undergo common-envelope (CE)
stages, losing in the process a tremendous amount of mass on dynamical
timescales. Five of the systems experience at least one Roche-lobe
overflow and CE stage (Kepler-1647 experiences three), and the binary
stars either shrink to very short orbits or coalesce; two systems
trigger a double-degenerate supernova explosion. Kepler’s
circumbinary planets predominantly remain gravitationally bound at the
end of the CE phase, migrate to larger orbits, and may gain significant
eccentricity; their orbital expansion can be more than an order of
magnitude and can occur over the course of a single planetary orbit. The
orbits these planets can reach are qualitatively consistent with those
of the currently known post-CE, eclipse-time variations circumbinary
candidates. Our results also show that circumbinary planets can
experience both modes of orbital expansion (adiabatic and nonadiabatic)
if their host binaries undergo more than one CE stage; multiplanet
circumbinary systems like Kepler-47 can experience both modes during the
same CE stage. Additionally, unlike Mercury orbiting the Sun, a
circumbinary planet with the same semimajor axis can survive the CE
evolution of a close binary star with a total mass of 1 {M}<SUB>⊙
</SUB>.Vantyghem, A. N.: Molecular Gas Along a Bright Hα Filament in 2A 0335+096 Revealed by ALMA
http://adsabs.harvard.edu/abs/2016ApJ...832..148V
We present ALMA CO(1-0) and CO(3-2) observations of the
brightest cluster galaxy (BCG) in the 2A 0335+096 galaxy cluster (z =
0.0346). The total molecular gas mass of 1.13 ± 0.15 ×
10<SUP>9</SUP> M <SUB>⊙</SUB> is divided into two components: a
nuclear region and a 7 kpc long dusty filament. The central molecular
gas component accounts for 3.2 ± 0.4 × 10<SUP>8</SUP> M
<SUB>⊙</SUB> of the total supply of cold gas. Instead of forming a
rotationally supported ring or disk, it is composed of two distinct,
blueshifted clumps south of the nucleus and a series of low-significance
redshifted clumps extending toward a nearby companion galaxy. The
velocity of the redshifted clouds increases with radius to a value
consistent with the companion galaxy, suggesting that an interaction
between these galaxies <20 Myr ago disrupted a pre-existing molecular
gas reservoir within the BCG. Most of the molecular gas, 7.8 ±
0.9 × 10<SUP>8</SUP> M <SUB>⊙</SUB>, is located in the
filament. The CO emission is co-spatial with a 10<SUP>4</SUP> K
emission-line nebula and soft X-rays from 0.5 keV gas, indicating that
the molecular gas has cooled out of the intracluster medium over a
period of 25-100 Myr. The filament trails an X-ray cavity,
suggesting that the gas has cooled from low-entropy gas that has been
lifted out of the cluster core and become thermally unstable. We are
unable to distinguish between inflow and outflow along the filament with
the present data. Cloud velocities along the filament are consistent
with gravitational free-fall near the plane of the sky, although their
increasing blueshifts with radius are consistent with outflow.Planck Collaboration: Planck intermediate results. XLIX. Parity-violation constraints from polarization data
http://adsabs.harvard.edu/abs/2016A%26A...596A.110P
Parity-violating extensions of the standard electromagnetic theory cause
in vacuo rotation of the plane of polarization of propagating photons.
This effect, also known as cosmic birefringence, has an impact on the
cosmic microwave background (CMB) anisotropy angular power spectra,
producing non-vanishing T-B and E-B correlations that are otherwise null
when parity is a symmetry. Here we present new constraints on an
isotropic rotation, parametrized by the angle α, derived from
Planck 2015 CMB polarization data. To increase the robustness of our
analyses, we employ two complementary approaches, in harmonic space and
in map space, the latter based on a peak stacking technique. The two
approaches provide estimates for α that are in agreement within
statistical uncertainties and are very stable against several
consistency tests.Considering the T-B and E-B information jointly, we
find α = 0fdg31 ± 0fdg05 ({stat.) ± 0fdg28 (syst.)}
from the harmonic analysis and α = 0fdg35 ± 0fdg05 ({stat.)
± 0fdg28 (syst.)} from the stacking approach. These constraints
are compatible with no parity violation and are dominated by the
systematic uncertainty in the orientation of Planck's
polarization-sensitive bolometers.Planck Collaboration: Planck intermediate results. XLVIII. Disentangling Galactic dust emission and cosmic infrared background anisotropies
http://adsabs.harvard.edu/abs/2016A%26A...596A.109P
Using the Planck 2015 data release (PR2) temperature maps, we separate
Galactic thermal dust emission from cosmic infrared background (CIB)
anisotropies. For this purpose, we implement a specifically tailored
component-separation method, the so-called generalized needlet internal
linear combination (GNILC) method, which uses spatial information (the
angular powerspectra) to disentangle the Galactic dust emission and CIB
anisotropies. We produce significantly improved all-sky maps of Planck
thermal dust emission, with reduced CIB contamination, at 353, 545, and
857 GHz. By reducing the CIB contamination of the thermal dust maps, we
provide more accurate estimates of the local dust temperature and dust
spectral index over the sky with reduced dispersion, especially at high
Galactic latitudes above b = ±20°. We find that the dust
temperature is T = (19.4 ± 1.3) K and the dust spectral index is
β = 1.6 ± 0.1 averaged over the whole sky, while T = (19.4
± 1.5) K and β = 1.6 ± 0.2 on 21% of the sky at high
latitudes. Moreover, subtracting the new CIB-removed thermal dust maps
from the CMB-removed Planck maps gives access to the CIB anisotropies
over 60% of the sky at Galactic latitudes |b| > 20°. Because they
are a significant improvement over previous Planck products, the GNILC
maps are recommended for thermal dust science. The new CIB maps can be
regarded as indirect tracers of the dark matter and they are recommended
for exploring cross-correlations with lensing and large-scale structure
optical surveys. The reconstructed GNILC thermal dust and CIB maps are
delivered as Planck products.Planck Collaboration: Planck intermediate results. XLVII. Planck constraints on reionization history
http://adsabs.harvard.edu/abs/2016A%26A...596A.108P
We investigate constraints on cosmic reionization extracted from the
Planck cosmic microwave background (CMB) data. We combine the Planck CMB
anisotropy data in temperature with the low-multipole polarization data
to fit ΛCDM models with various parameterizations of the
reionization history. We obtain a Thomson optical depth τ = 0.058
± 0.012 for the commonly adopted instantaneous reionization
model. This confirms, with data solely from CMB anisotropies, the low
value suggested by combining Planck 2015 results with other data sets,
and also reduces the uncertainties. We reconstruct the history of the
ionization fraction using either a symmetric or an asymmetric model for
the transition between the neutral and ionized phases. To determine
better constraints on the duration of the reionization process, we also
make use of measurements of the amplitude of the kinetic
Sunyaev-Zeldovich (kSZ) effect using additional information from the
high-resolution Atacama Cosmology Telescope and South Pole Telescope
experiments. The average redshift at which reionization occurs is found
to lie between z = 7.8 and 8.8, depending on the model of reionization
adopted. Using kSZ constraints and a redshift-symmetric reionization
model, we find an upper limit to the width of the reionization period of
Δz < 2.8. In all cases, we find that the Universe is ionized at
less than the 10% level at redshifts above z ≃ 10. This suggests
that an early onset of reionization is strongly disfavoured by the
Planck data. We show that this result also reduces the tension between
CMB-based analyses and constraints from other astrophysical sources.Planck Collaboration: Planck intermediate results. XLVI. Reduction of large-scale systematic effects in HFI polarization maps and estimation of the reionization optical depth
http://adsabs.harvard.edu/abs/2016A%26A...596A.107P
This paper describes the identification, modelling, and removal of
previously unexplained systematic effects in the polarization data of
the Planck High Frequency Instrument (HFI) on large angular scales,
including new mapmaking and calibration procedures, new and more
complete end-to-end simulations, and a set of robust internal
consistency checks on the resulting maps. These maps, at 100, 143, 217,
and 353 GHz, are early versions of those that will be released in final
form later in 2016. The improvements allow us to determine the cosmic
reionization optical depth τ using, for the first time, the
low-multipole EE data from HFI, reducing significantly the central value
and uncertainty, and hence the upper limit. Two different likelihood
procedures are used to constrain τ from two estimators of the CMB E-
and B-mode angular power spectra at 100 and 143 GHz, after debiasing the
spectra from a small remaining systematic contamination. These all give
fully consistent results. A further consistency test is performed using
cross-correlations derived from the Low Frequency Instrument maps of the
Planck 2015 data release and the new HFI data. For this purpose,
end-to-end analyses of systematic effects from the two instruments are
used to demonstrate the near independence of their dominant systematic
error residuals. The tightest result comes from the HFI-based τ
posterior distribution using the maximum likelihood power spectrum
estimator from EE data only, giving a value 0.055 ± 0.009. In a
companion paper these results are discussed in the context of the
best-fit PlanckΛCDM cosmological model and recent models of
reionization.Planck Collaboration: Planck intermediate results. XLV. Radio spectra of northern extragalactic radio sources
http://adsabs.harvard.edu/abs/2016A%26A...596A.106P
Continuum spectra covering centimetre to submillimetre wavelengths are
presented for a northern sample of 104 extragalactic radio sources,
mainly active galactic nuclei, based on four-epoch Planck data. The nine
Planck frequencies, from 30 to 857 GHz, are complemented by a set of
simultaneous ground-based radio observations between 1.1 and 37 GHz. The
single-survey Planck data confirm that the flattest high-frequency radio
spectral indices are close to zero, indicating that the original
accelerated electron energy spectrum is much harder than commonly
thought, with power-law index around 1.5 instead of the canonical 2.5.
The radio spectra peak at high frequencies and exhibit a variety of
shapes. For a small set of low-z sources, we find a spectral upturn at
high frequencies, indicating the presence of intrinsic cold dust.
Variability can generally be approximated by achromatic variations,
while sources with clear signatures of evolving shocks appear to be
limited to the strongest outbursts.Planck Collaboration: Planck intermediate results. XLIV. Structure of the Galactic magnetic field from dust polarization maps of the southern Galactic cap
http://adsabs.harvard.edu/abs/2016A%26A...596A.105P
Using data from the Planck satellite, we study the statistical
properties of interstellar dust polarization at high Galactic latitudes
around the south pole (b < -60°). Our aim is to advance the
understanding of the magnetized interstellar medium (ISM), and to
provide a modelling framework of the polarized dust foreground for use
in cosmic microwave background (CMB) component-separation procedures. We
examine the Stokes I, Q, and U maps at 353 GHz, and particularly the
statistical distribution of the polarization fraction (p) and angle
(ψ), in order to characterize the ordered and turbulent components
of the Galactic magnetic field (GMF) in the solar neighbourhood. The Q
and U maps show patterns at large angular scales, which we relate to the
mean orientation of the GMF towards Galactic coordinates
(l<SUB>0</SUB>,b<SUB>0</SUB>) = (70° ± 5°,24°
± 5°). The histogram of the observed p values shows a wide
dispersion up to 25%. The histogram of ψ has a standard deviation of
12° about the regular pattern expected from the ordered GMF. We
build a phenomenological model that connects the distributions of p and
ψ to a statistical description of the turbulent component of the
GMF, assuming a uniform effective polarization fraction (p<SUB>0</SUB>)
of dust emission. To compute the Stokes parameters, we approximate the
integration along the line of sight (LOS) as a sum over a set of N
independent polarization layers, in each of which the turbulent
component of the GMF is obtained from Gaussian realizations of a
power-law power spectrum. We are able to reproduce the observed p and
ψ distributions using a p<SUB>0</SUB> value of 26%, a ratio of 0.9
between the strengths of the turbulent and mean components of the GMF,
and a small value of N. The mean value of p (inferred from the fit of
the large-scale patterns in the Stokes maps) is 12 ± 1%. We
relate the polarization layers to the density structure and to the
correlation length of the GMF along the LOS. We emphasize the simplicity
of our model (involving only a few parameters), which can be easily
computed on the celestial sphere to produce simulated maps of dust
polarization. Our work is an important step towards a model that can be
used to assess the accuracy of component-separation methods in present
and future CMB experiments designed to search the B mode CMB
polarization from primordial gravity waves.Planck Collaboration: Planck intermediate results. XLIII. Spectral energy distribution of dust in clusters of galaxies
http://adsabs.harvard.edu/abs/2016A%26A...596A.104P
Although infrared (IR) overall dust emission from clusters of galaxies
has been statistically detected using data from the Infrared
Astronomical Satellite (IRAS), it has not been possible to sample the
spectral energy distribution (SED) of this emission over its peak, and
thus to break the degeneracy between dust temperature and mass. By
complementing the IRAS spectral coverage with Planck satellite data from
100 to 857 GHz, we provide new constraints on the IR spectrum of thermal
dust emission in clusters of galaxies. We achieve this by using a
stacking approach for a sample of several hundred objects from the
Planck cluster sample. This procedure averages out fluctuations from the
IR sky, allowing us to reach a significant detection of the faint
cluster contribution. We also use the large frequency range probed by
Planck, together with component-separation techniques, to remove the
contamination from both cosmic microwave background anisotropies and the
thermal Sunyaev-Zeldovich effect (tSZ) signal, which dominate at ν
≤ 353 GHz. By excluding dominant spurious signals or systematic
effects, averaged detections are reported at frequencies 353 GHz ≤
ν ≤ 5000 GHz. We confirm the presence of dust in clusters of
galaxies at low and intermediate redshifts, yielding an SED with a shape
similar to that of the Milky Way. Planck's resolution does not allow us
to investigate the detailed spatial distribution of this emission (e.g.
whether it comes from intergalactic dust or simply the dust content of
the cluster galaxies), but the radial distribution of the emission
appears to follow that of the stacked SZ signal, and thus the extent of
the clusters. The recovered SED allows us to constrain the dust mass
responsible for the signal and its temperature.Planck Collaboration: Planck intermediate results. XLII. Large-scale Galactic magnetic fields
http://adsabs.harvard.edu/abs/2016A%26A...596A.103P
Recent models for the large-scale Galactic magnetic fields in the
literature have been largely constrained by synchrotron emission and
Faraday rotation measures. We use three different but representative
models to compare their predicted polarized synchrotron and dust
emission with that measured by the Planck satellite. We first update
these models to match the Planck synchrotron products using a common
model for the cosmic-ray leptons. We discuss the impact on this analysis
of the ongoing problems of component separation in the Planck microwave
bands and of the uncertain cosmic-ray spectrum. In particular, the
inferred degree of ordering in the magnetic fields is sensitive to these
systematic uncertainties, and we further show the importance of
considering the expected variations in the observables in addition to
their mean morphology. We then compare the resulting simulated emission
to the observed dust polarization and find that the dust predictions do
not match the morphology in the Planck data but underpredict the dust
polarization away from the plane. We modify one of the models to roughly
match both observables at high latitudes by increasing the field
ordering in the thin disc near the observer. Though this specific
analysis is dependent on the component separation issues, we present the
improved model as a proof of concept for how these studies can be
advanced in future using complementary information from ongoing and
planned observational projects.Planck Collaboration: Planck intermediate results. XLI. A map of lensing-induced B-modes
http://adsabs.harvard.edu/abs/2016A%26A...596A.102P
The secondary cosmic microwave background (CMB) B-modes stem from the
post-decoupling distortion of the polarization E-modes due to the
gravitational lensing effect of large-scale structures. These
lensing-induced B-modes constitute both a valuable probe of the dark
matter distribution and an important contaminant for the extraction of
the primary CMB B-modes from inflation. Planck provides accurate nearly
all-sky measurements of both the polarization E-modes and the integrated
mass distribution via the reconstruction of the CMB lensing potential.
By combining these two data products, we have produced an all-sky
template map of the lensing-induced B-modes using a real-space algorithm
that minimizes the impact of sky masks. The cross-correlation of this
template with an observed (primordial and secondary) B-mode map can be
used to measure the lensing B-mode power spectrum at multipoles up to
2000. In particular, when cross-correlating with the B-mode contribution
directly derived from the Planck polarization maps, we obtain
lensing-induced B-mode power spectrum measurement at a significance
level of 12σ, which agrees with the theoretical expectation
derived from the Planck best-fit Λ cold dark matter model. This
unique nearly all-sky secondary B-mode template, which includes the
lensing-induced information from intermediate to small (10 ≲ ℓ
≲ 1000) angular scales, is delivered as part of the Planck 2015
public data release. It will be particularly useful for experiments
searching for primordial B-modes, such as BICEP2/Keck Array or LiteBIRD,
since it will enable an estimate to be made of the lensing-induced
contribution to the measured total CMB B-modes.Planck Collaboration: Planck intermediate results. XL. The Sunyaev-Zeldovich signal from the Virgo cluster
http://adsabs.harvard.edu/abs/2016A%26A...596A.101P
The Virgo cluster is the largest Sunyaev-Zeldovich (SZ) source in the
sky, both in terms of angular size and total integrated flux. Planck's
wide angular scale and frequency coverage, together with its high
sensitivity, enable a detailed study of this big object through the SZ
effect. Virgo is well resolved by Planck, showing an elongated structure
that correlates well with the morphology observed from X-rays, but
extends beyond the observed X-ray signal. We find good agreement between
the SZ signal (or Compton parameter, y<SUB>c</SUB>) observed by Planck
and the expected signal inferred from X-ray observations and simple
analytical models. Owing to its proximity to us, the gas beyond the
virial radius in Virgo can be studied with unprecedented sensitivity by
integrating the SZ signal over tens of square degrees. We study the
signal in the outskirts of Virgo and compare it with analytical models
and a constrained simulation of the environment of Virgo. Planck data
suggest that significant amounts of low-density plasma surround Virgo,
out to twice the virial radius. We find the SZ signal in the outskirts
of Virgo to be consistent with a simple model that extrapolates the
inferred pressure at lower radii, while assuming that the temperature
stays in the keV range beyond the virial radius. The observed signal is
also consistent with simulations and points to a shallow pressure
profile in the outskirts of the cluster. This reservoir of gas at large
radii can be linked with the hottest phase of the elusivewarm/hot
intergalactic medium. Taking the lack of symmetry of Virgo into account,
we find that a prolate model is favoured by the combination of SZ and
X-ray data, in agreement with predictions. Finally, based on the
combination of the same SZ and X-ray data, we constrain the total amount
of gas in Virgo. Under the hypothesis that the abundance of baryons in
Virgo is representative of the cosmic average, we also infer a distance
for Virgo of approximately 18 Mpc, in good agreement with previous
estimates.Planck Collaboration: Planck intermediate results. XXXIX. The Planck list of high-redshift source candidates
http://adsabs.harvard.edu/abs/2016A%26A...596A.100P
The Planck mission, thanks to its large frequency range and all-sky
coverage, has a unique potential for systematically detecting the
brightest, and rarest, submillimetre sources on the sky, including
distant objects in the high-redshift Universe traced by their dust
emission. A novel method, based on a component-separation procedure
using a combination of Planck and IRAS data, has been validated and
characterized on numerous simulations, and applied to select the most
luminous cold submillimetre sources with spectral energy distributions
peaking between 353 and 857 GHz at 5' resolution. A total of 2151 Planck
high-z source candidates (the PHZ) have been detected in the cleanest
26% of the sky, with flux density at 545 GHz above 500 mJy. Embedded in
the cosmic infrared background close to the confusion limit, these
high-z candidates exhibit colder colours than their surroundings,
consistent with redshifts z > 2, assuming a dust temperature of
T<SUB>xgal</SUB> = 35 K and a spectral index of β<SUB>xgal</SUB> =
1.5. Exhibiting extremely high luminosities, larger than
10<SUP>14</SUP>L<SUB>⊙</SUB>, the PHZ objects may be made of
multiple galaxies or clumps at high redshift, as suggested by a first
statistical analysis based on a comparison with number count models.
Furthermore, first follow-up observations obtained from optical to
submillimetre wavelengths, which can be found in companion papers, have
confirmed that this list consists of two distinct populations. A small
fraction (around 3%) of the sources have been identified as strongly
gravitationally lensed star-forming galaxies at redshift 2 to 4, while
the vast majority of the PHZ sources appear as overdensities of dusty
star-forming galaxies, having colours consistent with being at z > 2,
and may be considered as proto-cluster candidates. The PHZ provides an
original sample, which is complementary to the Planck Sunyaev-Zeldovich
Catalogue (PSZ2); by extending the population of virialized massive
galaxy clusters detected below z < 1.5 through their SZ signal to a
population of sources at z > 1.5, the PHZ may contain the progenitors
of today's clusters. Hence the Planck list of high-redshift source
candidates opens a new window on the study of the early stages of
structure formation, particularly understanding the intensively
star-forming phase at high-z.
The catalogue is only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A
href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/A100">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/A100</A>Soler, J. D.: Magnetic field morphology in nearby molecular clouds as revealed by starlight and submillimetre polarization
http://adsabs.harvard.edu/abs/2016A%26A...596A..93S
Within four nearby (d < 160 pc) molecular clouds, we statistically
evaluated the structure of the interstellar magnetic field, projected on
the plane of the sky and integrated along the line of sight, as inferred
from the polarized thermal emission of Galactic dust observed by Planck
at 353 GHz and from the optical and near-infrared polarization of
background starlight. We compared the dispersion of the field
orientation directly in vicinities with an area equivalent to that
subtended by the Planck effective beam at 353 GHz (10') and using the
second-order structure functions of the field orientation angles. We
found that the average dispersion of the starlight-inferred field
orientations within 10'-diameter vicinities is less than 20°, and
that at these scales the mean field orientation is on average within
5° of that inferred from the submillimetre polarization observations
in the considered regions. We also found that the dispersion of
starlight polarization orientations and the polarization fractions
within these vicinities are well reproduced by a Gaussian model of the
turbulent structure of the magnetic field, in agreement with the
findings reported by the Planck Collaboration at scales ℓ > 10'
and for comparable column densities. At scales ℓ > 10', we found
differences of up to 14.̊7 between the second-order structure
functions obtained from starlight and submillimetre polarization
observations in the same positions in the plane of the sky, but
comparison with a Gaussian model of the turbulent structure of the
magnetic field indicates that these differences are small and are
consistent with the difference in angular resolution between both
techniques. The differences between the second-order structure functions
calculated with each technique suggests that the increase in the angular
resolution obtained with the starlight polarization observations does
not introduce significant corrections to the dispersion of polarization
orientations used in the calculation of the molecular-cloud-scale
magnetic field strengths reported in previous studies by the Planck
Collaboration.Abbott, B. P.: Results of the deepest all-sky survey for continuous gravitational waves on LIGO S6 data running on the Einstein@Home volunteer distributed computing project
http://adsabs.harvard.edu/abs/2016PhRvD..94j2002A
We report results of a deep all-sky search for periodic gravitational
waves from isolated neutron stars in data from the S6 LIGO science run.
The search was possible thanks to the computing power provided by the
volunteers of the Einstein@Home distributed computing project. We find
no significant signal candidate and set the most stringent upper limits
to date on the amplitude of gravitational wave signals from the target
population. At the frequency of best strain sensitivity, between 170.5
and 171 Hz we set a 90% confidence upper limit of 5.5
×10<SUP>-25</SUP> , while at the high end of our frequency range,
around 505 Hz, we achieve upper limits ≃10<SUP>-24</SUP> . At 230
Hz we can exclude sources with ellipticities greater than
10<SUP>-6</SUP> within 100 pc of Earth with fiducial value of the
principal moment of inertia of 10<SUP>38</SUP> kg m<SUP>2</SUP> . If we
assume a higher (lower) gravitational wave spin-down we constrain
farther (closer) objects to higher (lower) ellipticities.Abbott, B. P.: First targeted search for gravitational-wave bursts from core-collapse supernovae in data of first-generation laser interferometer detectors
http://adsabs.harvard.edu/abs/2016PhRvD..94j2001A
We present results from a search for gravitational-wave bursts
coincident with two core-collapse supernovae observed optically in 2007
and 2011. We employ data from the Laser Interferometer
Gravitational-wave Observatory (LIGO), the Virgo gravitational-wave
observatory, and the GEO 600 gravitational-wave observatory. The
targeted core-collapse supernovae were selected on the basis of (1)
proximity (within approximately 15 Mpc), (2) tightness of observational
constraints on the time of core collapse that defines the
gravitational-wave search window, and (3) coincident operation of at
least two interferometers at the time of core collapse. We find no
plausible gravitational-wave candidates. We present the probability of
detecting signals from both astrophysically well-motivated and more
speculative gravitational-wave emission mechanisms as a function of
distance from Earth, and discuss the implications for the detection of
gravitational waves from core-collapse supernovae by the upgraded
Advanced LIGO and Virgo detectors.Sravan, N.: Strongly time-variable ultraviolet metal-line emission from the circum-galactic medium of high-redshift galaxies
http://adsabs.harvard.edu/abs/2016MNRAS.463..120S
We use cosmological simulations from the Feedback In Realistic
Environments project, which implement a comprehensive set of stellar
feedback processes, to study ultraviolet (UV) metal-line emission from
the circum-galactic medium of high-redshift (z = 2-4) galaxies. Our
simulations cover the halo mass range M<SUB>h</SUB> ˜ 2 ×
10<SUP>11</SUP>-8.5 × 10<SUP>12</SUP> M<SUB>⊙</SUB> at z = 2,
representative of Lyman break galaxies. Of the transitions we analyse,
the low-ionization C III (977 Å) and Si III (1207 Å)
emission lines are the most luminous, with C IV (1548 Å) and Si IV
(1394 Å) also showing interesting spatially extended structures.
The more massive haloes are on average more UV-luminous. The UV
metal-line emission from galactic haloes in our simulations arises
primarily from collisionally ionized gas and is strongly time variable,
with peak-to-trough variations of up to ˜2 dex. The peaks of UV
metal-line luminosity correspond closely to massive and energetic mass
outflow events, which follow bursts of star formation and inject
sufficient energy into galactic haloes to power the metal-line emission.
The strong time variability implies that even some relatively low-mass
haloes may be detectable. Conversely, flux-limited samples will be
biased towards haloes whose central galaxy has recently experienced a
strong burst of star formation. Spatially extended UV metal-line
emission around high-redshift galaxies should be detectable by current
and upcoming integral field spectrographs such as the Multi Unit
Spectroscopic Explorer on the Very Large Telescope and Keck Cosmic Web
Imager.Tacik, N.: Initial data for black hole-neutron star binaries, with rotating stars
http://adsabs.harvard.edu/abs/2016CQGra..33v5012T
The coalescence of a neutron star with a black hole is a primary science
target of ground-based gravitational wave detectors. Constraining or
measuring the neutron star spin directly from gravitational wave
observations requires knowledge of the dependence of the emission
properties of these systems on the neutron star spin. This paper lays
foundations for this task, by developing a numerical method to construct
initial data for black hole-neutron star binaries with arbitrary
spin on the neutron star. We demonstrate the robustness of the code by
constructing initial-data sets in large regions of the parameter space.
In addition to varying the neutron star spin-magnitude and
spin-direction, we also explore neutron star compactness, mass-ratio,
black hole spin, and black hole spin-direction. Specifically, we are
able to construct initial data sets with neutron stars spinning near
centrifugal break-up, and with black hole spins as large as
{S}<SUB>{BH</SUB>}/{M}<SUB>{BH</SUB>}<SUP>2</SUP>=0.99.Usman, S. A.: The PyCBC search for gravitational waves from compact binary coalescence
http://adsabs.harvard.edu/abs/2016CQGra..33u5004U
We describe the PyCBC search for gravitational waves from compact-object
binary coalescences in advanced gravitational-wave detector data. The
search was used in the first Advanced Laser Interferometer
Gravitational-wave Observatory (LIGO) observing run and unambiguously
identified two black hole binary mergers, GW150914 and GW151226. At its
core, the PyCBC search performs a matched-filter search for binary
merger signals using a bank of gravitational-wave template waveforms. We
provide a complete description of the search pipeline including the
steps used to mitigate the effects of noise transients in the data,
identify candidate events and measure their statistical significance.
The analysis is able to measure false-alarm rates as low as one per
million years, required for confident detection of signals. Using data
from initial LIGO's sixth science run, we show that the new analysis
reduces the background noise in the search, giving a 30 % increase in
sensitive volume for binary neutron star systems over previous searches.Hoang, T.: A Unified Model of Grain Alignment: Radiative Alignment of Interstellar Grains with Magnetic Inclusions
http://adsabs.harvard.edu/abs/2016ApJ...831..159H
The radiative torque (RAT) alignment of interstellar grains with
ordinary paramagnetic susceptibilities has been supported by earlier
studies. The alignment of such grains depends on the so-called RAT
parameter q <SUP>max</SUP>, which is determined by the grain shape. In
this paper, we elaborate on our model of RAT alignment for grains with
enhanced magnetic susceptibility due to iron inclusions, such that RAT
alignment is magnetically enhanced, which we term the MRAT mechanism.
Such grains can be aligned with high angular momentum at the so-called
high-J attractor points, achieving a high degree of alignment. Using our
analytical model of RATs, we derive the critical value of the magnetic
relaxation parameter δ <SUB>m</SUB> to produce high-J attractor
points as functions of q <SUP>max</SUP> and the anisotropic radiation
angle relative to the magnetic field ψ. We find that if about 10% of
the total iron abundance present in silicate grains is forming iron
clusters, this is sufficient to produce high-J attractor points for all
reasonable values of q <SUP>max</SUP>. To calculate the degree of grain
alignment, we carry out numerical simulations of MRAT alignment by
including stochastic excitations from gas collisions and magnetic
fluctuations. We show that large grains can achieve perfect alignment
when the high-J attractor point is present, regardless of the values of
q <SUP>max</SUP>. Our obtained results pave the way for the physical
modeling of polarized thermal dust emission as well as magnetic dipole
emission. We also find that millimeter-sized grains in accretion disks
may be aligned with the magnetic field if they are incorporated with
iron nanoparticles.Mieda, E.: IROCKS: Spatially Resolved Kinematics of z ˜ 1 Star-forming Galaxies
http://adsabs.harvard.edu/abs/2016ApJ...831...78M
We present results from the Intermediate Redshift OSIRIS Chemo-Kinematic
Survey (IROCKS) for sixteen z ˜ 1 and one z ˜ 1.4 star-forming
galaxies. All galaxies were observed with OSIRIS with the laser guide
star adaptive optics system at Keck Observatory. We use rest-frame
nebular Hα emission lines to trace morphologies and kinematics of
ionized gas in star-forming galaxies on sub-kiloparsec physical scales.
We observe elevated velocity dispersions (σ ≳ 50 km
s<SUP>-1</SUP>) seen in z > 1.5 galaxies persist at z ˜ 1
in the integrated galaxies. Using an inclined disk model and the ratio
of v/σ , we find that 1/3 of the z ˜ 1 sample are disk
candidates while the other 2/3 of the sample are dominated by
merger-like and irregular sources. We find that including extra
attenuation toward H ii regions derived from stellar population
synthesis modeling brings star formation rates (SFRs) using Hα and
stellar population fit into a better agreement. We explore the
properties of the compact Hα sub-component, or
“clump,” at z ˜ 1 and find that they follow a similar
size-luminosity relation as local H ii regions but are scaled-up
by an order of magnitude with higher luminosities and sizes. Comparing
the z ˜ 1 clumps to other high-redshift clump studies, we determine
that the clump SFR surface density evolves as a function of redshift.
This suggests clump formation is directly related to the gas fraction in
these systems and may support disk fragmentation as their formation
mechanism since gas fraction scales with redshift.Abbott, B. P.: Binary Black Hole Mergers in the First Advanced LIGO Observing Run
http://adsabs.harvard.edu/abs/2016PhRvX...6d1015A
The first observational run of the Advanced LIGO detectors, from
September 12, 2015 to January 19, 2016, saw the first detections of
gravitational waves from binary black hole mergers. In this paper, we
present full results from a search for binary black hole merger signals
with total masses up to 100 M<SUB>⊙</SUB> and detailed implications
from our observations of these systems. Our search, based on
general-relativistic models of gravitational-wave signals from binary
black hole systems, unambiguously identified two signals, GW150914 and
GW151226, with a significance of greater than 5 σ over the
observing period. It also identified a third possible signal, LVT151012,
with substantially lower significance and with an 87% probability of
being of astrophysical origin. We provide detailed estimates of the
parameters of the observed systems. Both GW150914 and GW151226 provide
an unprecedented opportunity to study the two-body motion of a
compact-object binary in the large velocity, highly nonlinear regime. We
do not observe any deviations from general relativity, and we place
improved empirical bounds on several high-order post-Newtonian
coefficients. From our observations, we infer stellar-mass binary black
hole merger rates lying in the range 9 - 240 Gpc<SUP>-3</SUP>
yr<SUP>-1</SUP> . These observations are beginning to inform
astrophysical predictions of binary black hole formation rates and
indicate that future observing runs of the Advanced detector network
will yield many more gravitational-wave detections.Baumann, D.: New Target for Cosmic Axion Searches
http://adsabs.harvard.edu/abs/2016PhRvL.117q1301B
Future cosmic microwave background experiments have the potential to
probe the density of relativistic species at the subpercent level. This
sensitivity allows light thermal relics to be detected up to arbitrarily
high decoupling temperatures. Conversely, the absence of a detection
would require extra light species never to have been in equilibrium with
the Standard Model. In this Letter, we exploit this feature to
demonstrate the sensitivity of future cosmological observations to the
couplings of axions to photons, gluons, and charged fermions. In many
cases, the constraints achievable from cosmology will surpass existing
bounds from laboratory experiments and astrophysical observations by
orders of magnitude.Gralla, S. E.: Transient instability of rapidly rotating black holes
http://adsabs.harvard.edu/abs/2016PhRvD..94h4017G
We analytically study the linear response of a near-extremal Kerr black
hole to external scalar, electromagnetic, and gravitational field
perturbations. We show that the energy density, electromagnetic field
strength, and tidal force experienced by infalling observers exhibit
transient growth near the horizon. The growth lasts arbitrarily long in
the extremal limit, reproducing the horizon instability of extremal
Kerr. We explain these results in terms of near-horizon geometry and
discuss potential astrophysical implications.Van Laerhoven, C. L.: Reaching Rural Canadian Communities in the Yukon and Alberta
http://adsabs.harvard.edu/abs/2016DPS....4841705V
Canada is very large geographically, so many rural communities are very
far from major centers. People in such communities are at a severe
disadvantage when it comes to in-person interaction with science or
scientists because resources tend to be directed at large population
centers, where more people can be reached for the same amount of effort.
While this geographic distance can be mitigated by doing outreach over
the internet, there is at some level no substitute for showing up in
person with e.g. meteorites in hand. Due to where various members of my
family are located, I have occasion to visit Whitehorse, YT and Andrew,
AB (~1.5 hour drive north-east of Edmonton) and have taken advantage of
trips to these locations to do astronomy outreach in both schools and
public libraries. I will discuss how I arranged school and library
visits and general observations from my experience doing outreach in
rural Canadian communities.Tamayo, D.: Machine Learning Algorithms For Predicting the Instability Timescales of Compact Planetary Systems
http://adsabs.harvard.edu/abs/2016DPS....4830907T
The Kepler mission has uncovered hundreds of compact multi-planet
systems. The dynamical pathways to instability in these compact systems
and their associated timescales are not well understood theoretically.
However, long-term stability is often used as a constraint to narrow
down the space of orbital solutions from the transit data. This requires
a large suite of N-body integrations that can each take several weeks to
complete. This computational bottleneck is therefore an important
limitation in our ability to characterize compact multi-planet
systems.From suites of numerical simulations, previous studies have fit
simple scaling relations between the instability timescale and various
system parameters. However, the numerically simulated systems can
deviate strongly from these empirical fits.We present a new approach to
the problem using machine learning algorithms that have enjoyed success
across a broad range of high-dimensional industry applications. In
particular, we have generated large training sets of direct N-body
integrations of synthetic compact planetary systems to train several
regression models (support vector machine, gradient boost) that predict
the instability timescale. We find that ensembling these models predicts
the instability timescale of planetary systems better than previous
approaches using the simple scaling relations mentioned above.Finally,
we will discuss how these models provide a powerful tool for not only
understanding the current Kepler multi-planet sample, but also for
characterizing and shaping the radial-velocity follow-up strategies of
multi-planet systems from the upcoming Transiting Exoplanet Survey
Satellite (TESS) mission, given its shorter observation baselines.Van Laerhoven, C. L.: Stability of evenly spaced, tightly packed systems of Earth-massed planets around M-dwarfs
http://adsabs.harvard.edu/abs/2016DPS....4830906V
M-dwarf stars are prime targets in the search for habitable exoplanets
because the stars are smaller and the habitable zone is quite close to
the star. Surveys have revealed a considerable number of tightly packed
planetary systems around small stars, and this raises the question of
how closely planets can be packed together and stay stable for billions
of years. Using numerical simulations, we have investigated the
stability of hypothetical systems comprised of several Earth-mass
planets around an M-dwarf star, where the planets' orbits are all evenly
spaced in mutual Hill Radii. We reproduce the obvious: that, in general,
the more tightly packed a system is the faster it will go unstable.
However, we see structure superimposed on this general trend that can
cause a system's lifetime to differ by several orders of magnitude over
a small difference in planet spacing. We will discuss implications for
the maximum number Earth-mass planets that can fit in an M-dwarfs'
habitable zone.Petrovich, C.: Warm Jupiters from Secular Planet-Planet Interactions
http://adsabs.harvard.edu/abs/2016ApJ...829..132P
Most warm Jupiters (gas-giant planets with 0.1 {{au}}≲ a≲ 1
au) have pericenter distances that are too large for significant orbital
migration by tidal friction. We study the possibility that the warm
Jupiters are undergoing secular eccentricity oscillations excited by an
outer companion (a planet or star) in an eccentric and/or mutually
inclined orbit. In this model, the warm Jupiters migrate periodically,
in the high-eccentricity phase of the oscillation, but are typically
observed at lower eccentricities. We show that in this model the
steady-state eccentricity distribution of the warm Jupiters is
approximately flat, which is consistent with the observed distribution
if we restrict the sample to warm Jupiters with detected outer planetary
companions. The eccentricity distribution of warm Jupiters without
companions exhibits a peak at e≲ 0.2 that must be explained by a
different formation mechanism. Based on a population synthesis study, we
find that high-eccentricity migration excited by an outer planetary
companion (1) can account for ˜ 20 % of the warm Jupiters and most
of the warm Jupiters with e≳ 0.4; and (2) can produce most of the
observed population of hot Jupiters, with a semimajor axis distribution
that matches the observations, but fails to account adequately for ˜
60 % of hot Jupiters with projected obliquities ≲ 20^\circ . Thus
˜ 20 % of the warm Jupiters and ˜ 60 % of the hot Jupiters can
be produced by high-eccentricity migration. We also provide predictions
for the expected mutual inclinations and spin-orbit angles of the
planetary systems with hot and warm Jupiters produced by
high-eccentricity migration.Pen, U.-L.: Shocks in the Early Universe
http://adsabs.harvard.edu/abs/2016PhRvL.117m1301P
We point out a surprising consequence of the usually assumed initial
conditions for cosmological perturbations. Namely, a spectrum of
Gaussian, linear, adiabatic, scalar, growing mode perturbations not only
creates acoustic oscillations of the kind observed on very large scales
today, it also leads to the production of shocks in the radiation fluid
of the very early Universe. Shocks cause departures from local thermal
equilibrium as well as create vorticity and gravitational waves. For a
scale-invariant spectrum and standard model physics, shocks form for
temperatures 1 GeV <T <1 0<SUP>7</SUP> GeV . For more general
power spectra, such as have been invoked to form primordial black holes,
shock formation and the consequent gravitational wave emission provide a
signal detectable by current and planned gravitational wave experiments,
allowing them to strongly constrain conditions present in the primordial
Universe as early as 10<SUP>-30</SUP> sec after the big bang.Chisari, N.: Redshift and luminosity evolution of the intrinsic alignments of galaxies in Horizon-AGN
http://adsabs.harvard.edu/abs/2016MNRAS.461.2702C
Intrinsic galaxy shape and angular momentum alignments can arise in
cosmological large-scale structure due to tidal interactions or galaxy
formation processes. Cosmological hydrodynamical simulations have
recently come of age as a tool to study these alignments and their
contamination to weak gravitational lensing. We probe the redshift and
luminosity evolution of intrinsic alignments in Horizon-AGN between z =
0 and 3 for galaxies with an r-band absolute magnitude of M<SUB>r</SUB>
≤ -20. Alignments transition from being radial at low redshifts and
high luminosities, dominated by the contribution of ellipticals, to
being tangential at high redshift and low luminosities, where discs
dominate the signal. This cannot be explained by the evolution of the
fraction of ellipticals and discs alone: intrinsic evolution in the
amplitude of alignments is necessary. The alignment amplitude of
elliptical galaxies alone is smaller in amplitude by a factor of
≃2, but has similar luminosity and redshift evolution as in current
observations and in the non-linear tidal alignment model at projected
separations of ≳1 Mpc. Alignments of discs are null in projection
and consistent with current low-redshift observations. The combination
of the two populations yields an overall amplitude a factor of ≃4
lower than observed alignments of luminous red galaxies with a steeper
luminosity dependence. The restriction on accurate galaxy shapes implies
that the galaxy population in the simulation is complete only to
M<SUB>r</SUB> ≤ -20. Higher resolution simulations will be necessary
to avoid extrapolation of the intrinsic alignment predictions to the
range of luminosities probed by future surveys.Tricco, T. S.: A comparison between grid and particle methods on the small-scale dynamo in magnetized supersonic turbulence
http://adsabs.harvard.edu/abs/2016MNRAS.461.1260T
We perform a comparison between the smoothed particle
magnetohydrodynamics (SPMHD) code, PHANTOM, and the Eulerian grid-based
code, FLASH, on the small-scale turbulent dynamo in driven, Mach 10
turbulence. We show, for the first time, that the exponential growth and
saturation of an initially weak magnetic field via the small-scale
dynamo can be successfully reproduced with SPMHD. The two codes agree on
the behaviour of the magnetic energy spectra, the saturation level of
magnetic energy, and the distribution of magnetic field strengths during
the growth and saturation phases. The main difference is that the dynamo
growth rate, and its dependence on resolution, differs between the
codes, caused by differences in the numerical dissipation and shock
capturing schemes leading to differences in the effective Prandtl number
in PHANTOM and FLASH.Oppermann, N.: The Euclidean distribution of fast radio bursts
http://adsabs.harvard.edu/abs/2016MNRAS.461..984O
We investigate whether current data on the distribution of observed flux
densities of fast radio bursts (FRBs) are consistent with a constant
source density in Euclidean space. We use the number of FRBs detected in
two surveys with different characteristics along with the observed
signal-to-noise ratios of the detected FRBs in a formalism similar to a
V/V<SUB>max</SUB>-test to constrain the distribution of flux densities.
We find consistency between the data and a Euclidean distribution. Any
extension of this model is therefore not data-driven and needs to be
motivated separately. As a byproduct we also obtain new improved limits
for the FRB rate at 1.4 GHz, which had not been constrained in this way
before.Sifón, C.: The Atacama Cosmology Telescope: dynamical masses for 44 SZ-selected galaxy clusters over 755 square degrees
http://adsabs.harvard.edu/abs/2016MNRAS.461..248S
We present galaxy velocity dispersions and dynamical mass estimates for
44 galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect by
the Atacama Cosmology Telescope. Dynamical masses for 18 clusters are
reported here for the first time. Using N-body simulations, we model the
different observing strategies used to measure the velocity dispersions
and account for systematic effects resulting from these strategies. We
find that the galaxy velocity distributions may be treated as isotropic,
and that an aperture correction of up to 7 per cent in the velocity
dispersion is required if the spectroscopic galaxy sample is
sufficiently concentrated towards the cluster centre. Accounting for the
radial profile of the velocity dispersion in simulations enables
consistent dynamical mass estimates regardless of the observing
strategy. Cluster masses M<SUB>200</SUB> are in the range (1-15) ×
10<SUP>14</SUP> M<SUB>⊙</SUB>. Comparing with masses estimated from
the SZ distortion assuming a gas pressure profile derived from X-ray
observations gives a mean SZ-to-dynamical mass ratio of 1.10 ±
0.13, but there is an additional 0.14 systematic uncertainty due to the
unknown velocity bias; the statistical uncertainty is dominated by the
scatter in the mass-velocity dispersion scaling relation. This ratio is
consistent with previous determinations at these mass scales.Chen, X.: The future of primordial features with 21 cm tomography
http://adsabs.harvard.edu/abs/2016JCAP...09..023C
Detecting a deviation from a featureless primordial power spectrum of
fluctuations would give profound insight into the physics of the
primordial Universe. Depending on their nature, primordial features can
either provide direct evidence for the inflation scenario or pin down
details of the inflation model. Thus far, using the cosmic microwave
background (CMB) we have only been able to put stringent constraints on
the amplitude of features, but no significant evidence has been found
for such signals. Here we explore the limit of the experimental reach in
constraining such features using 21 cm tomography at high redshift. A
measurement of the 21 cm power spectrum from the Dark Ages is generally
considered as the ideal experiment for early Universe physics, with
potentially access to a large number of modes. We consider three
different categories of theoretically motivated models: the sharp
feature models, resonance models, and standard clock models. We study
the improvements on bounds on features as a function of the total number
of observed modes and identify parameter degeneracies. The detectability
depends critically on the amplitude, frequency and scale-location of the
features, as well as the angular and redshift resolution of the
experiment. We quantify these effects by considering different fiducial
models. Our forecast shows that a cosmic variance limited 21 cm
experiment measuring fluctuations in the redshift range 30 <= z <=
100 with a 0.01-MHz bandwidth and sub-arcminute angular resolution could
potentially improve bounds by several orders of magnitude for most
features compared to current Planck bounds. At the same time, 21 cm
tomography also opens up a unique window into features that are located
on very small scales.Planck Collaboration: Planck 2015 results. XXVII. The second Planck catalogue of Sunyaev-Zeldovich sources
http://adsabs.harvard.edu/abs/2016A%26A...594A..27P
We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ)
sources detected from the 29 month full-mission data. The catalogue
(PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced
and the deepest systematic all-sky surveyof galaxy clusters. It contains
1653 detections, of which 1203 are confirmed clusters with identified
counterparts in external data sets, and is the first SZ-selected cluster
survey containing >10<SUP>3</SUP> confirmed clusters. We present a
detailed analysis of the survey selection function in terms of its
completeness and statistical reliability, placing a lower limit of 83%
on the purity. Using simulations, we find that the estimates of the SZ
strength parameter Y<SUB>5R500</SUB>are robust to pressure-profile
variation and beam systematics, but accurate conversion to
Y<SUB>500</SUB> requires the use of prior information on the cluster
extent. We describe the multi-wavelength search for counterparts in
ancillary data, which makes use of radio, microwave, infra-red, optical,
and X-ray data sets, and which places emphasis on the robustness of the
counterpart match. We discuss the physical properties of the new sample
and identify a population of low-redshift X-ray under-luminous clusters
revealed by SZ selection. These objects appear in optical and SZ surveys
with consistent properties for their mass, but are almost absent from
ROSAT X-ray selected samples.Planck Collaboration: Planck 2015 results. XXVI. The Second Planck Catalogue of Compact Sources
http://adsabs.harvard.edu/abs/2016A%26A...594A..26P
The Second Planck Catalogue of Compact Sources is a list of discrete
objects detected in single-frequency maps from the full duration of the
Planck mission and supersedes previous versions. It consists of compact
sources, both Galactic and extragalactic, detected over the entire sky.
Compact sources detected in the lower frequency channels are assigned to
the PCCS2, while at higher frequencies they are assigned to one of two
subcatalogues, the PCCS2 or PCCS2E, depending on their location on the
sky. The first of these (PCCS2) covers most of the sky and allows the
user to produce subsamples at higher reliabilities than the target 80%
integral reliability of the catalogue. The second (PCCS2E) contains
sources detected in sky regions where the diffuse emission makes it
difficult to quantify the reliability of the detections. Both the PCCS2
and PCCS2E include polarization measurements, in the form of polarized
flux densities, or upper limits, and orientation angles for all seven
polarization-sensitive Planck channels. The improved data-processing of
the full-mission maps and their reduced noise levels allow us to
increase the number of objects in the catalogue, improving its
completeness for the target 80% reliability as compared with the
previous versions, the PCCS and the Early Release Compact Source
Catalogue (ERCSC).Planck Collaboration: Planck 2015 results. XXV. Diffuse low-frequency Galactic foregrounds
http://adsabs.harvard.edu/abs/2016A%26A...594A..25P
We discuss the Galactic foreground emission between 20 and 100 GHz based
on observations by Planck and WMAP. The total intensity in this part of
the spectrum is dominated by free-free and spinning dust emission,
whereas the polarized intensity is dominated by synchrotron emission.
The Commander component-separation tool has been used to separate the
various astrophysical processes in total intensity. Comparison with
radio recombination line templates verifies the recovery of the
free-free emission along the Galactic plane. Comparison of the
high-latitude Hα emission with our free-free map shows residuals
that correlate with dust optical depth, consistent with a fraction
(≈30%) of Hα having been scattered by high-latitude dust. We
highlight a number of diffuse spinning dust morphological features at
high latitude. There is substantial spatial variation in the spinning
dust spectrum, with the emission peak (in I<SUB>ν</SUB>) ranging from
below 20 GHz to more than 50 GHz. There is a strong tendency for the
spinning dust component near many prominent H ii regions to have a
higher peak frequency, suggesting that this increase in peak frequency
is associated with dust in the photo-dissociation regions around the
nebulae. The emissivity of spinning dust in these diffuse regions is of
the same order as previous detections in the literature. Over the entire
sky, the Commander solution finds more anomalous microwave emission
(AME) than the WMAP component maps, at the expense of synchrotron and
free-free emission. This can be explained by the difficulty in
separating multiple broadband components with a limited number of
frequency maps. Future surveys, particularly at 5-20 GHz, will greatly
improve the separation by constraining the synchrotron spectrum. We
combine Planck and WMAP data to make the highest signal-to-noise ratio
maps yet of the intensity of the all-sky polarized synchrotron emission
at frequencies above a few GHz. Most of the high-latitude polarized
emission is associated with distinct large-scale loops and spurs, and we
re-discuss their structure. We argue that nearly all the emission at
40deg > l > -90deg is part of the Loop I structure, and show that
the emission extends much further in to the southern Galactic hemisphere
than previously recognised, giving Loop I an ovoid rather than circular
outline. However, it does not continue as far as the "Fermi
bubble/microwave haze", making it less probable that these are part of
the same structure. We identify a number of new faint features in the
polarized sky, including a dearth of polarized synchrotron emission
directly correlated with a narrow, roughly 20deg long filament seen in
Hα at high Galactic latitude. Finally, we look for evidence of
polarized AME, however many AME regions are significantly contaminated
by polarized synchrotron emission, and we find a 2σ upper limit of
1.6% in the Perseus region.Planck Collaboration: Planck 2015 results. XXIV. Cosmology from Sunyaev-Zeldovich cluster counts
http://adsabs.harvard.edu/abs/2016A%26A...594A..24P
We present cluster counts and corresponding cosmological constraints
from the Planck full mission data set. Our catalogue consists of 439
clusters detected via their Sunyaev-Zeldovich (SZ) signal down to a
signal-to-noise ratio of 6, and is more than a factor of 2 larger than
the 2013 Planck cluster cosmology sample. The counts are consistent with
those from 2013 and yield compatible constraints under the same
modelling assumptions. Taking advantage of the larger catalogue, we
extend our analysis to the two-dimensional distribution in redshift and
signal-to-noise. We use mass estimates from two recent studies of
gravitational lensing of background galaxies by Planck clusters to
provide priors on the hydrostatic bias parameter, (1-b). In addition, we
use lensing of cosmic microwave background (CMB) temperature
fluctuations by Planck clusters as an independent constraint on this
parameter. These various calibrations imply constraints on the
present-day amplitude of matter fluctuations in varying degrees of
tension with those from the Planck analysis of primary fluctuations in
the CMB; for the lowest estimated values of (1-b) the tension is mild,
only a little over one standard deviation, while it remains substantial
(3.7σ) for the largest estimated value. We also examine
constraints on extensions to the base flat ΛCDM model by
combining the cluster and CMB constraints. The combination appears to
favour non-minimal neutrino masses, but this possibility does little to
relieve the overall tension because it simultaneously lowers the implied
value of the Hubble parameter, thereby exacerbating the discrepancy with
most current astrophysical estimates. Improving the precision of cluster
mass calibrations from the current 10%-level to 1% would significantly
strengthen these combined analyses and provide a stringent test of the
base ΛCDM model.Planck Collaboration: Planck 2015 results. XXII. A map of the thermal Sunyaev-Zeldovich effect
http://adsabs.harvard.edu/abs/2016A%26A...594A..22P
We have constructed all-sky Compton parameters maps, y-maps, of the
thermal Sunyaev-Zeldovich (tSZ) effect by applying specifically tailored
component separation algorithms to the 30 to 857 GHz frequency channel
maps from the Planck satellite. These reconstructed y-maps are delivered
as part of the Planck 2015 release. The y-maps are characterized in
terms of noise properties and residual foreground contamination, mainly
thermal dust emission at large angular scales, and cosmic infrared
background and extragalactic point sources at small angular scales.
Specific masks are defined to minimize foreground residuals and
systematics. Using these masks, we compute the y-map angular power
spectrum and higher order statistics. From these we conclude that the
y-map is dominated by tSZ signal in the multipole range, 20
<ℓ< 600. We compare the measured tSZ power spectrum and higher
order statistics to various physically motivated models and discuss the
implications of our results in terms of cluster physics and cosmology.Planck Collaboration: Planck 2015 results. XXI. The integrated Sachs-Wolfe effect
http://adsabs.harvard.edu/abs/2016A%26A...594A..21P
This paper presents a study of the integrated Sachs-Wolfe (ISW) effect
from the Planck 2015 temperature and polarization data release. This
secondary cosmic microwave background (CMB) anisotropy caused by the
large-scale time-evolving gravitational potential is probed from
different perspectives. The CMB is cross-correlated with different
large-scale structure (LSS) tracers: radio sources from the NVSS
catalogue; galaxies from the optical SDSS and the infrared WISE surveys;
and the Planck 2015 convergence lensing map. The joint cross-correlation
of the CMB with the tracers yields a detection at 4σ where most of
the signal-to-noise is due to the Planck lensing and the NVSS radio
catalogue. In fact, the ISW effect is detected from the Planck data only
at ≈3σ (through the ISW-lensing bispectrum), which is similar
to the detection level achieved by combining the cross-correlation
signal coming from all the galaxy catalogues mentioned above. We study
the ability of the ISW effect to place constraints on the dark-energy
parameters; in particular, we show that Ω<SUB>Λ</SUB> is
detected at more than 3σ. This cross-correlation analysis is
performed only with the Planck temperature data, since the polarization
scales available in the 2015 release do not permit significant
improvement of the CMB-LSS cross-correlation detectability.
Nevertheless, the Planck polarization data are used to study the
anomalously large ISW signal previously reported through the aperture
photometry on stacked CMB features at the locations of known
superclusters and supervoids, which is in conflict with ΛCDM
expectations. We find that the current Planck polarization data do not
exclude that this signal could be caused by the ISW effect. In addition,
the stacking of the Planck lensing map on the locations of
superstructures exhibits a positive cross-correlation with these
large-scale structures. Finally, we have improved our previous
reconstruction of the ISW temperature fluctuations by combining the
information encoded in all the previously mentioned LSS tracers. In
particular, we construct a map of the ISW secondary anisotropies and the
corresponding uncertainties map, obtained from simulations. We also
explore the reconstruction of the ISW anisotropies caused by the
large-scale structure traced by the 2MASS Photometric Redshift Survey
(2MPZ) by directly inverting the density field into the gravitational
potential field.Planck Collaboration: Planck 2015 results. XX. Constraints on inflation
http://adsabs.harvard.edu/abs/2016A%26A...594A..20P
We present the implications for cosmic inflation of the Planck
measurements of the cosmic microwave background (CMB) anisotropies in
both temperature and polarization based on the full Planck survey, which
includes more than twice the integration time of the nominal survey used
for the 2013 release papers. The Planck full mission temperature data
and a first release of polarization data on large angular scales measure
the spectral index of curvature perturbations to be n<SUB>s</SUB> =
0.968 ± 0.006 and tightly constrain its scale dependence to
dn<SUB>s</SUB>/ dlnk = -0.003 ± 0.007 when combined with the
Planck lensing likelihood. When the Planck high-ℓ polarization data
are included, the results are consistent and uncertainties are further
reduced. The upper bound on the tensor-to-scalar ratio is
r<SUB>0.002</SUB>< 0.11 (95% CL). This upper limit is consistent with
the B-mode polarization constraint r< 0.12 (95% CL) obtained from a
joint analysis of the BICEP2/Keck Array and Planck data. These results
imply that V(φ) ∝ φ<SUP>2</SUP> and natural inflation are
now disfavoured compared to models predicting a smaller tensor-to-scalar
ratio, such as R<SUP>2</SUP> inflation. We search for several physically
motivated deviations from a simple power-law spectrum of curvature
perturbations, including those motivated by a reconstruction of the
inflaton potential not relying on the slow-roll approximation. We find
that such models are not preferred, either according to a Bayesian model
comparison or according to a frequentist simulation-based analysis.
Three independent methods reconstructing the primordial power spectrum
consistently recover a featureless and smooth P<SUB>R</SUB>(k) over the
range of scales 0.008 Mpc<SUP>-1</SUP> ≲ k ≲ 0.1
Mpc<SUP>-1</SUP>. At large scales, each method finds deviations from a
power law, connected to a deficit at multipoles ℓ ≈ 20-40 in the
temperature power spectrum, but at an uncompelling statistical
significance owing to the large cosmic variance present at these
multipoles. By combining power spectrum and non-Gaussianity bounds, we
constrain models with generalized Lagrangians, including Galileon models
and axion monodromy models. The Planck data are consistent with
adiabatic primordial perturbations, and the estimated values for the
parameters of the base Λ cold dark matter (ΛCDM) model are
not significantly altered when more general initial conditions are
admitted. In correlated mixed adiabatic and isocurvature models, the 95%
CL upper bound for the non-adiabatic contribution to the observed CMB
temperature variance is | α<SUB>non - adi</SUB> | < 1.9%, 4.0%,
and 2.9% for CDM, neutrino density, and neutrino velocity isocurvature
modes, respectively. We have tested inflationary models producing an
anisotropic modulation of the primordial curvature power spectrum
findingthat the dipolar modulation in the CMB temperature field induced
by a CDM isocurvature perturbation is not preferred at a statistically
significant level. We also establish tight constraints on a possible
quadrupolar modulation of the curvature perturbation. These results are
consistent with the Planck 2013 analysis based on the nominal mission
data and further constrain slow-roll single-field inflationary models,
as expected from the increased precision of Planck data using the full
set of observations.Planck Collaboration: Planck 2015 results. XVIII. Background geometry and topology of the Universe
http://adsabs.harvard.edu/abs/2016A%26A...594A..18P
Maps of cosmic microwave background (CMB) temperature and polarization
from the 2015 release of Planck data provide the highestquality full-sky
view of the surface of last scattering available to date. This enables
us to detect possible departures from a globally isotropic cosmology. We
present the first searches using CMB polarization for correlations
induced by a possible non-trivial topology with a fundamental domain
that intersects, or nearly intersects, the last-scattering surface (at
comoving distance χ<SUB>rec</SUB>), both via a direct scan for
matched circular patterns at the intersections and by an optimal
likelihood calculation for specific topologies. We specialize to flat
spaces with cubic toroidal (T3) and slab (T1) topologies, finding that
explicit searches for the latter are sensitive to other topologies with
antipodal symmetry. These searches yield no detection of a compact
topology with a scale below the diameter of the last-scattering surface.
The limits on the radius ℛ<SUB>i</SUB> of the largest sphere
inscribed in the fundamental domain (at log-likelihood ratio
Δlnℒ > -5 relative to a simply-connected flat Planck
best-fit model) are: ℛ<SUB>i</SUB> > 0.97 χ<SUB>rec</SUB>
for the T3 cubic torus; and ℛ<SUB>i</SUB> > 0.56
χ<SUB>rec</SUB> for the T1 slab. The limit for the T3 cubic torus
from the matched-circles search is numerically equivalent,
ℛ<SUB>i</SUB> > 0.97 χ<SUB>rec</SUB> at 99% confidence
level from polarization data alone. We also perform a Bayesian search
for an anisotropic global Bianchi VII<SUB>h</SUB> geometry. In the
non-physical setting, where the Bianchi cosmology is decoupled from the
standard cosmology, Planck temperature data favour the inclusion of a
Bianchi component with a Bayes factor of at least 2.3 units of
log-evidence. However, the cosmological parameters that generate this
pattern are in strong disagreement with those found from CMB anisotropy
data alone. Fitting the induced polarization pattern for this model to
the Planck data requires an amplitude of -0.10 ± 0.04 compared to
the value of + 1 if the model were to be correct. In the physically
motivated setting, where the Bianchi parameters are coupled and fitted
simultaneously with the standard cosmological parameters, we find no
evidence for a Bianchi VII<SUB>h</SUB> cosmology and constrain the
vorticity of such models to (ω/H)<SUB>0</SUB> < 7.6 ×
10<SUP>-10</SUP> (95% CL).Planck Collaboration: Planck 2015 results. XVII. Constraints on primordial non-Gaussianity
http://adsabs.harvard.edu/abs/2016A%26A...594A..17P
The Planck full mission cosmic microwave background (CMB) temperature
and E-mode polarization maps are analysed to obtain constraints on
primordial non-Gaussianity (NG). Using three classes of optimal
bispectrum estimators - separable template-fitting (KSW), binned, and
modal - we obtain consistent values for the primordial local,
equilateral, and orthogonal bispectrum amplitudes, quoting as our final
result from temperature alone ƒ<SUP>local</SUP><SUB>NL</SUB> = 2.5
± 5.7, ƒ<SUP>equil</SUP><SUB>NL</SUB>= -16 ± 70, ,
and ƒ<SUP>ortho</SUP><SUB>NL</SUB> = -34 ± 32 (68% CL,
statistical). Combining temperature and polarization data we obtain
ƒ<SUP>local</SUP><SUB>NL</SUB> = 0.8 ± 5.0,
ƒ<SUP>equil</SUP><SUB>NL</SUB>= -4 ± 43, and
ƒ<SUP>ortho</SUP><SUB>NL</SUB> = -26 ± 21 (68% CL,
statistical). The results are based on comprehensive cross-validation of
these estimators on Gaussian and non-Gaussian simulations, are stable
across component separation techniques, pass an extensive suite of
tests, and are consistent with estimators based on measuring the
Minkowski functionals of the CMB. The effect of time-domain de-glitching
systematics on the bispectrum is negligible. In spite of these test
outcomes we conservatively label the results including polarization data
as preliminary, owing to a known mismatch of the noise model in
simulations and the data. Beyond estimates of individual shape
amplitudes, we present model-independent, three-dimensional
reconstructions of the Planck CMB bispectrum and derive constraints on
early universe scenarios that generate primordial NG, including general
single-field models of inflation, axion inflation, initial state
modifications, models producing parity-violating tensor bispectra, and
directionally dependent vector models. We present a wide survey of
scale-dependent feature and resonance models, accounting for the "look
elsewhere" effect in estimating the statistical significance of
features. We also look for isocurvature NG, and find no signal, but we
obtain constraints that improve significantly with the inclusion of
polarization. The primordial trispectrum amplitude in the local model is
constrained to be 𝓰<SUP>local</SUP><SUB>NL</SUB> = (-0.9
± 7.7 ) X 10<SUP>4</SUP>(68% CL statistical), and we perform an
analysis of trispectrum shapes beyond the local case. The global picture
that emerges is one of consistency with the premises of the ΛCDM
cosmology, namely that the structure we observe today was sourced by
adiabatic, passive, Gaussian, and primordial seed perturbations.Planck Collaboration: Planck 2015 results. XV. Gravitational lensing
http://adsabs.harvard.edu/abs/2016A%26A...594A..15P
We present the most significant measurement of the cosmic microwave
background (CMB) lensing potential to date (at a level of 40σ),
using temperature and polarization data from the Planck 2015
full-mission release. Using a polarization-only estimator, we detect
lensing at a significance of 5σ. We cross-check the accuracy of
our measurement using the wide frequency coverage and complementarity of
the temperature and polarization measurements. Public products based on
this measurement include an estimate of the lensing potential over
approximately 70% of the sky, an estimate of the lensing potential power
spectrum in bandpowers for the multipole range 40 ≤ L ≤ 400, and
an associated likelihood for cosmological parameter constraints. We find
good agreement between our measurement of the lensing potential power
spectrum and that found in the ΛCDM model that best fits the
Planck temperature and polarization power spectra. Using the lensing
likelihood alone we obtain a percent-level measurement of the parameter
combination σ<SUB>8</SUB>Ω<SUP>0.25</SUP><SUB>m</SUB> =
0.591 ± 0.021. We combine our determination of the lensing
potential with the E-mode polarization, also measured by Planck, to
generate an estimate of the lensing B-mode. We show that this lensing
B-mode estimate is correlated with the B-modes observed directly by
Planck at the expected level and with a statistical significance of
10σ, confirming Planck's sensitivity to this known sky signal. We
also correlate our lensing potential estimate with the large-scale
temperature anisotropies, detecting a cross-correlation at the 3σ
level, as expected because of dark energy in the concordance ΛCDM
model.Planck Collaboration: Planck 2015 results. XIV. Dark energy and modified gravity
http://adsabs.harvard.edu/abs/2016A%26A...594A..14P
We study the implications of Planck data for models of dark energy (DE)
and modified gravity (MG) beyond the standard cosmological constant
scenario. We start with cases where the DE only directly affects the
background evolution, considering Taylor expansions of the equation of
state w(a), as well as principal component analysis and
parameterizations related to the potential of a minimally coupled DE
scalar field. When estimating the density of DE at early times, we
significantly improve present constraints and find that it has to be
below ~2% (at 95% confidence) of the critical density, even when forced
to play a role for z < 50 only. We then move to general
parameterizations of the DE or MG perturbations that encompass both
effective field theories and the phenomenology of gravitational
potentials in MG models. Lastly, we test a range of specific models,
such as k-essence, f(R) theories, and coupled DE. In addition to the
latest Planck data, for our main analyses, we use background constraints
from baryonic acoustic oscillations, type-Ia supernovae, and local
measurements of the Hubble constant. We further show the impact of
measurements of the cosmological perturbations, such as redshift-space
distortions and weak gravitational lensing. These additional probes are
important tools for testing MG models and for breaking degeneracies that
are still present in the combination of Planck and background data sets.
All results that include only background parameterizations (expansion of
the equation of state, early DE, general potentials in minimally-coupled
scalar fields or principal component analysis) are in agreement with
ΛCDM. When testing models that also change perturbations (even
when the background is fixed to ΛCDM), some tensions appear in a
few scenarios: the maximum one found is ~2σ for Planck TT+lowP
when parameterizing observables related to the gravitational potentials
with a chosen time dependence; the tension increases to, at most,
3σ when external data sets are included. It however disappears
when including CMB lensing.Planck Collaboration: Planck 2015 results. XIII. Cosmological parameters
http://adsabs.harvard.edu/abs/2016A%26A...594A..13P
This paper presents cosmological results based on full-mission Planck
observations of temperature and polarization anisotropies of the cosmic
microwave background (CMB) radiation. Our results are in very good
agreement with the 2013 analysis of the Planck nominal-mission
temperature data, but with increased precision. The temperature and
polarization power spectra are consistent with the standard
spatially-flat 6-parameter ΛCDM cosmology with a power-law
spectrum of adiabatic scalar perturbations (denoted "base ΛCDM"
in this paper). From the Planck temperature data combined with Planck
lensing, for this cosmology we find a Hubble constant, H<SUB>0</SUB> =
(67.8 ± 0.9) km s<SUP>-1</SUP>Mpc<SUP>-1</SUP>, a matter density
parameter Ω<SUB>m</SUB> = 0.308 ± 0.012, and a tilted
scalar spectral index with n<SUB>s</SUB> = 0.968 ± 0.006,
consistent with the 2013 analysis. Note that in this abstract we quote
68% confidence limits on measured parameters and 95% upper limits on
other parameters. We present the first results of polarization
measurements with the Low Frequency Instrument at large angular scales.
Combined with the Planck temperature and lensing data, these
measurements give a reionization optical depth of τ = 0.066 ±
0.016, corresponding to a reionization redshift of
z_re=8.8<SUP>+1.7<SUB>-1.4</SUB>. These results are consistent with
those from WMAP polarization measurements cleaned for dust emission
using 353-GHz polarization maps from the High Frequency Instrument. We
find no evidence for any departure from base ΛCDM in the neutrino
sector of the theory; for example, combining Planck observations with
other astrophysical data we find N<SUB>eff</SUB> = 3.15 ± 0.23
for the effective number of relativistic degrees of freedom, consistent
with the value N<SUB>eff</SUB> = 3.046 of the Standard Model of particle
physics. The sum of neutrino masses is constrained to ∑
m<SUB>ν</SUB> < 0.23 eV. The spatial curvature of our Universe is
found to be very close to zero, with | Ω<SUB>K</SUB> | < 0.005.
Adding a tensor component as a single-parameter extension to base
ΛCDM we find an upper limit on the tensor-to-scalar ratio of
r<SUB>0.002</SUB>< 0.11, consistent with the Planck 2013 results and
consistent with the B-mode polarization constraints from a joint
analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP
B-mode data to our analysis leads to a tighter constraint of
r<SUB>0.002</SUB> < 0.09 and disfavours inflationarymodels with a
V(φ) ∝ φ<SUP>2</SUP> potential. The addition of Planck
polarization data leads to strong constraints on deviations from a
purely adiabatic spectrum of fluctuations. We find no evidence for any
contribution from isocurvature perturbations or from cosmic defects.
Combining Planck data with other astrophysical data, including Type Ia
supernovae, the equation of state of dark energy is constrained to w =
-1.006 ± 0.045, consistent with the expected value for a
cosmological constant. The standard big bang nucleosynthesis predictions
for the helium and deuterium abundances for the best-fit Planck base
ΛCDM cosmology are in excellent agreement with observations. We
also constraints on annihilating dark matter and on possible deviations
from the standard recombination history. In neither case do we find no
evidence for new physics. The Planck results for base ΛCDM are in
good agreement with baryon acoustic oscillation data and with the JLA
sample of Type Ia supernovae. However, as in the 2013 analysis, the
amplitude of the fluctuation spectrum is found to be higher than
inferred from some analyses of rich cluster counts and weak
gravitational lensing. We show that these tensions cannot easily be
resolved with simple modifications of the base ΛCDM cosmology.
Apart from these tensions, the base ΛCDM cosmology provides an
excellent description of the Planck CMB observations and many other
astrophysical data sets.
</SUP>Planck Collaboration: Planck 2015 results. XII. Full focal plane simulations
http://adsabs.harvard.edu/abs/2016A%26A...594A..12P
We present the 8th full focal plane simulation set (FFP8), deployed in
support of the Planck 2015 results. FFP8 consists of 10 fiducial mission
realizations reduced to 18 144 maps, together with the most massive
suite of Monte Carlo realizations of instrument noise and CMB ever
generated, comprising 10<SUP>4</SUP> mission realizations reduced to
about 10<SUP>6</SUP> maps. The resulting maps incorporate the dominant
instrumental, scanning, and data analysis effects, and the remaining
subdominant effects will be included in future updates. Generated at a
cost of some 25 million CPU-hours spread across multiple
high-performance-computing (HPC) platforms, FFP8 is used to validate and
verify analysis algorithms and their implementations, and to remove
biases from and quantify uncertainties in the results of analyses of the
real data.Planck Collaboration: Planck 2015 results. XI. CMB power spectra, likelihoods, and robustness of parameters
http://adsabs.harvard.edu/abs/2016A%26A...594A..11P
This paper presents the Planck 2015 likelihoods, statistical
descriptions of the 2-point correlationfunctions of the cosmic microwave
background (CMB) temperature and polarization fluctuations that account
for relevant uncertainties, both instrumental and astrophysical in
nature. They are based on the same hybrid approach used for the previous
release, i.e., a pixel-based likelihood at low multipoles (ℓ< 30)
and a Gaussian approximation to the distribution of cross-power spectra
at higher multipoles. The main improvements are the use of more and
better processed data and of Planck polarization information, along with
more detailed models of foregrounds and instrumental uncertainties. The
increased redundancy brought by more than doubling the amount of data
analysed enables further consistency checks and enhanced immunity to
systematic effects. It also improves the constraining power of Planck,
in particular with regard to small-scale foreground properties. Progress
in the modelling of foreground emission enables the retention of a
larger fraction of the sky to determine the properties of the CMB, which
also contributes to the enhanced precision of the spectra. Improvements
in data processing and instrumental modelling further reduce
uncertainties. Extensive tests establish the robustness and accuracy of
the likelihood results, from temperature alone, from polarization alone,
and from their combination. For temperature, we also perform a full
likelihood analysis of realistic end-to-end simulations of the
instrumental response to the sky, which were fed into the actual data
processing pipeline; this does not reveal biases from residual low-level
instrumental systematics. Even with the increase in precision and
robustness, the ΛCDM cosmological model continues to offer a very
good fit to the Planck data. The slope of the primordial scalar
fluctuations, n<SUB>s</SUB>, is confirmed smaller than unity at more
than 5σ from Planck alone. We further validate the robustness of
the likelihood results against specific extensions to the baseline
cosmology, which are particularly sensitive to data at high multipoles.
For instance, the effective number of neutrino species remains
compatible with the canonical value of 3.046. For this first detailed
analysis of Planck polarization spectra, we concentrate at high
multipoles on the E modes, leaving the analysis of the weaker B modes to
future work. At low multipoles we use temperature maps at all Planck
frequencies along with a subset of polarization data. These data take
advantage of Planck's wide frequency coverage to improve the separation
of CMB and foreground emission. Within the baseline ΛCDM
cosmology this requires τ = 0.078 ± 0.019 for the
reionization optical depth, which is significantly lower than estimates
without the use of high-frequency data for explicit monitoring of dust
emission. At high multipoles we detect residual systematic errors in E
polarization, typically at the μK<SUP>2</SUP> level; we therefore
choose to retain temperature information alone for high multipoles as
the recommended baseline, in particular for testing non-minimal models.
Nevertheless, the high-multipole polarization spectra from Planck are
already good enough to enable a separate high-precision determination of
the parameters of the ΛCDM model, showing consistency with those
established independently from temperature information alone.Planck Collaboration: Planck 2015 results. X. Diffuse component separation: Foreground maps
http://adsabs.harvard.edu/abs/2016A%26A...594A..10P
Planck has mapped the microwave sky in temperature over nine frequency
bands between 30 and 857 GHz and in polarization over seven frequency
bands between 30 and 353 GHz in polarization. In this paper we consider
the problem of diffuse astrophysical component separation, and process
these maps within a Bayesian framework to derive an internally
consistent set of full-sky astrophysical component maps. Component
separation dedicated to cosmic microwave background (CMB) reconstruction
is described in a companion paper. For the temperature analysis, we
combine the Planck observations with the 9-yr Wilkinson Microwave
Anisotropy Probe (WMAP) sky maps and the Haslam et al. 408 MHz map, to
derive a joint model of CMB, synchrotron, free-free, spinning dust, CO,
line emission in the 94 and 100 GHz channels, and thermal dust emission.
Full-sky maps are provided for each component, with an angular
resolution varying between 7.´5 and 1deg. Global parameters
(monopoles, dipoles, relative calibration, and bandpass errors) are
fitted jointly with the sky model, and best-fit values are tabulated.
For polarization, the model includes CMB, synchrotron, and thermal dust
emission. These models provide excellent fits to the observed data, with
rms temperature residuals smaller than 4μK over 93% of the sky for
all Planck frequencies up to 353 GHz, and fractional errors smaller than
1% in the remaining 7% of the sky. The main limitations of the
temperature model at the lower frequencies are internal degeneracies
among the spinning dust, free-free, and synchrotron components;
additional observations from external low-frequency experiments will be
essential to break these degeneracies. The main limitations of the
temperature model at the higher frequencies are uncertainties in the 545
and 857 GHz calibration and zero-points. For polarization, the main
outstanding issues are instrumental systematics in the 100-353 GHz bands
on large angular scales in the form of temperature-to-polarization
leakage, uncertainties in the analogue-to-digital conversion, and
corrections for the very long time constant of the bolometer detectors,
all of which are expected to improve in the near future.Planck Collaboration: Planck 2015 results. VII. High Frequency Instrument data processing: Time-ordered information and beams
http://adsabs.harvard.edu/abs/2016A%26A...594A...7P
The Planck High Frequency Instrument (HFI) has observed the full sky at
six frequencies (100, 143, 217, 353, 545, and 857 GHz) in intensity and
at four frequencies in linear polarization (100, 143, 217, and 353 GHz).
In order to obtain sky maps, the time-ordered information (TOI)
containing the detector and pointing samples must be processed and the
angular response must be assessed. The full mission TOI is included in
the Planck 2015 release. This paper describes the HFI TOI and beam
processing for the 2015 release. HFI calibration and map making are
described in a companion paper. The main pipeline has been modified
since the last release (2013 nominal mission in intensity only), by
including a correction for the nonlinearity of the warm readout and by
improving the model of the bolometer time response. The beam processing
is an essential tool that derives the angular response used in all the
Planck science papers and we report an improvement in the effective beam
window function uncertainty of more than a factor of 10 relative to
the2013 release. Noise correlations introduced by pipeline filtering
function are assessed using dedicated simulations. Angular cross-power
spectra using data sets that are decorrelated in time are immune to the
main systematic effects.Planck Collaboration: Planck 2015 results. VI. LFI mapmaking
http://adsabs.harvard.edu/abs/2016A%26A...594A...6P
This paper describes the mapmaking procedure applied to Planck Low
Frequency Instrument (LFI) data. The mapmaking step takes as input the
calibrated timelines and pointing information. The main products are sky
maps of I, Q, and U Stokes components. For the first time, we present
polarization maps at LFI frequencies. The mapmaking algorithm is based
on a destriping technique, which is enhanced with a noise prior. The
Galactic region is masked to reduce errors arising from bandpass
mismatch and high signal gradients. We apply horn-uniform radiometer
weights to reduce the effects of beam-shape mismatch. The algorithm is
the same as used for the 2013 release, apart from small changes in
parameter settings. We validate the procedure through simulations.
Special emphasis is put on the control of systematics, which is
particularly important for accurate polarization analysis. We also
produce low-resolution versions of the maps and corresponding noise
covariance matrices. These serve as input in later analysis steps and
parameter estimation. The noise covariance matrices are validated
through noise Monte Carlo simulations. The residual noise in the map
products is characterized through analysis of half-ring maps, noise
covariance matrices, and simulations.Planck Collaboration: Planck 2015 results. II. Low Frequency Instrument data processings
http://adsabs.harvard.edu/abs/2016A%26A...594A...2P
We present an updated description of the Planck Low Frequency Instrument
(LFI) data processing pipeline, associated with the 2015 data release.
We point out the places where our results and methods have remained
unchanged since the 2013 paper and we highlight the changes made for the
2015 release, describing the products (especially timelines) and the
ways in which they were obtained. We demonstrate that the pipeline is
self-consistent (principally based on simulations) and report all null
tests. For the first time, we present LFI maps in Stokes Q and U
polarization. We refer to other related papers where more detailed
descriptions of the LFI data processing pipeline may be found if needed.Planck Collaboration: Planck 2015 results. I. Overview of products and scientific results
http://adsabs.harvard.edu/abs/2016A%26A...594A...1P
The European Space Agency's Planck satellite, which is dedicated to
studying the early Universe and its subsequent evolution, was launched
on 14 May 2009. It scanned the microwave and submillimetre sky
continuously between 12 August 2009 and 23 October 2013. In February
2015, ESA and the Planck Collaboration released the second set of
cosmology products based ondata from the entire Planck mission,
including both temperature and polarization, along with a set of
scientific and technical papers and a web-based explanatory supplement.
This paper gives an overview of the main characteristics of the data and
the data products in the release, as well as the associated cosmological
and astrophysical science results and papers. The data products include
maps of the cosmic microwave background (CMB), the thermal
Sunyaev-Zeldovich effect, diffuse foregrounds in temperature and
polarization, catalogues of compact Galactic and extragalactic sources
(including separate catalogues of Sunyaev-Zeldovich clusters and
Galactic cold clumps), and extensive simulations of signals and noise
used in assessing uncertainties and the performance of the analysis
methods. The likelihood code used to assess cosmological models against
the Planck data is described, along with a CMB lensing likelihood.
Scientific results include cosmological parameters derived from CMB
power spectra, gravitational lensing, and cluster counts, as well as
constraints on inflation, non-Gaussianity, primordial magnetic fields,
dark energy, and modified gravity, and new results on low-frequency
Galactic foregrounds.Berger, P.: Holographic beam mapping of the CHIME pathfinder array
http://adsabs.harvard.edu/abs/2016SPIE.9906E..0DB
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder
radio telescope is currently surveying the northern hemisphere between
400 and 800 MHz. By mapping the large scale structure of neutral
hydrogen through its redshifted 21 cm line emission between z 0.8-2.5
CHIME will contribute to our understanding of Dark Energy. Bright
astrophysical foregrounds must be separated from the neutral hydrogen
signal, a task which requires precise characterization of the polarized
telescope beams. Using the DRAO John A. Galt 26 m telescope, we have
developed a holography instrument and technique for mapping the CHIME
Pathfinder beams. We report the status of the instrument and initial
results of this effort.Johannsen, T.: Testing General Relativity with Accretion-Flow Imaging of Sgr A*
http://adsabs.harvard.edu/abs/2016PhRvL.117i1101J
The Event Horizon Telescope is a global, very long baseline
interferometer capable of probing potential deviations from the Kerr
metric, which is believed to provide the unique description of
astrophysical black holes. Here, we report an updated constraint on the
quadrupolar deviation of Sagittarius A<SUP>*</SUP> within the context of
a radiatively inefficient accretion flow model in a quasi-Kerr
background. We also simulate near-future constraints obtainable by the
forthcoming eight-station array and show that in this model already a
one-day observation can measure the spin magnitude to within 0.005, the
inclination to within 0.09°, the position angle to within 0.04°,
and the quadrupolar deviation to within 0.005 at 3 σ confidence.
Thus, we are entering an era of high-precision strong gravity
measurements.Abbott, B. P.: Comprehensive all-sky search for periodic gravitational waves in the sixth science run LIGO data
http://adsabs.harvard.edu/abs/2016PhRvD..94d2002A
We report on a comprehensive all-sky search for periodic gravitational
waves in the frequency band 100-1500 Hz and with a frequency time
derivative in the range of [-1.18 ,+1.00 ] ×1 0<SUP>-8</SUP> Hz /s
. Such a signal could be produced by a nearby spinning and slightly
nonaxisymmetric isolated neutron star in our galaxy. This search uses
the data from the initial LIGO sixth science run and covers a larger
parameter space with respect to any past search. A Loosely Coherent
detection pipeline was applied to follow up weak outliers in both
Gaussian (95% recovery rate) and non-Gaussian (75% recovery rate) bands.
No gravitational wave signals were observed, and upper limits were
placed on their strength. Our smallest upper limit on worst-case
(linearly polarized) strain amplitude h<SUB>0</SUB> is 9.7 ×1
0<SUP>-25</SUP> near 169 Hz, while at the high end of our frequency
range we achieve a worst-case upper limit of 5.5 ×1
0<SUP>-24</SUP> . Both cases refer to all sky locations and entire range
of frequency derivative values.Codis, S.: The large-scale correlations of multicell densities and profiles: implications for cosmic variance estimates
http://adsabs.harvard.edu/abs/2016MNRAS.460.1598C
In order to quantify the error budget in the measured probability
distribution functions of cell densities, the two-point statistics of
cosmic densities in concentric spheres is investigated. Bias functions
are introduced as the ratio of their two-point correlation function to
the two-point correlation of the underlying dark matter distribution.
They describe how cell densities are spatially correlated. They are
computed here via the so-called large deviation principle in the
quasi-linear regime. Their large-separation limit is presented and
successfully compared to simulations for density and density slopes:
this regime is shown to be rapidly reached allowing to get sub-percent
precision for a wide range of densities and variances. The corresponding
asymptotic limit provides an estimate of the cosmic variance of standard
concentric cell statistics applied to finite surveys. More generally, no
assumption on the separation is required for some specific moments of
the two-point statistics, for instance when predicting the generating
function of cumulants containing any powers of concentric densities in
one location and one power of density at some arbitrary distance from
the rest. This exact `one external leg' cumulant generating function is
used in particular to probe the rate of convergence of the
large-separation approximation.Codis, S.: Encircling the dark: constraining dark energy via cosmic density in spheres
http://adsabs.harvard.edu/abs/2016MNRAS.460.1549C
The recently published analytic probability density function for the
mildly non-linear cosmic density field within spherical cells is used to
build a simple but accurate maximum likelihood estimate for the redshift
evolution of the variance of the density, which, as expected, is shown
to have smaller relative error than the sample variance. This estimator
provides a competitive probe for the equation of state of dark energy,
reaching a few per cent accuracy on w<SUB>p</SUB> and w<SUB>a</SUB> for
a Euclid-like survey. The corresponding likelihood function can take
into account the configuration of the cells via their relative
separations. A code to compute one-cell-density probability density
functions for arbitrary initial power spectrum, top-hat smoothing and
various spherical-collapse dynamics is made available online, so as to
provide straightforward means of testing the effect of alternative dark
energy models and initial power spectra on the low-redshift matter
distribution.Uhlemann, C.: Back in the saddle: large-deviation statistics of the cosmic log-density field
http://adsabs.harvard.edu/abs/2016MNRAS.460.1529U
We present a first principle approach to obtain analytical predictions
for spherically averaged cosmic densities in the mildly non-linear
regime that go well beyond what is usually achieved by standard
perturbation theory. A large deviation principle allows us to compute
the leading order cumulants of average densities in concentric cells. In
this symmetry, the spherical collapse model leads to cumulant generating
functions that are robust for finite variances and free of critical
points when logarithmic density transformations are implemented. They
yield in turn accurate density probability distribution functions (PDFs)
from a straightforward saddle-point approximation valid for all density
values. Based on this easy-to-implement modification, explicit analytic
formulas for the evaluation of the one- and two-cell PDF are provided.
The theoretical predictions obtained for the PDFs are accurate to a few
per cent compared to the numerical integration, regardless of the
density under consideration and in excellent agreement with N-body
simulations for a wide range of densities. This formalism should prove
valuable for accurately probing the quasi-linear scales of low-redshift
surveys for arbitrary primordial power spectra.Battaglia, N.: Weak-lensing mass calibration of the Atacama Cosmology Telescope equatorial Sunyaev-Zeldovich cluster sample with the Canada-France-Hawaii telescope stripe 82 survey
http://adsabs.harvard.edu/abs/2016JCAP...08..013B
Mass calibration uncertainty is the largest systematic effect for using
clusters of galaxies to constrain cosmological parameters. We present
weak lensing mass measurements from the Canada-France-Hawaii Telescope
Stripe 82 Survey for galaxy clusters selected through their high
signal-to-noise thermal Sunyaev-Zeldovich (tSZ) signal measured with the
Atacama Cosmology Telescope (ACT). For a sample of 9 ACT clusters with a
tSZ signal-to-noise greater than five the average weak lensing mass is
(4.8±0.8) ×10<SUP>14</SUP> M<SUB>solar</SUB>, consistent
with the tSZ mass estimate of (4.70±1.0) ×10<SUP>14</SUP>
M<SUB>solar</SUB> which assumes a universal pressure profile for the
cluster gas. Our results are consistent with previous weak-lensing
measurements of tSZ-detected clusters from the Planck satellite. When
comparing our results, we estimate the Eddington bias correction for the
sample intersection of Planck and weak-lensing clusters which was
previously excluded.Silvestro, P. C.: Crop Monitoring Using European and Chinese Medium Resolution Satellite Data
http://adsabs.harvard.edu/abs/2016ESASP.739E.110S
The ultimate aim of this work is to develop methods for the assimilation
of the biophysical variables estimated by remote sensing in a suitable
crop growth model. Two strategies were followed, one based on the use of
Leaf Area Index (LAI) estimated by optical data, and the other based on
the use of biomass estimated by SAR. The first one estimates LAI from
the reflectance measured by the optical sensors on board of HJ1A, HJ1B
and Landsat, using a method based on the training of artificial neural
networks (ANN) with PROSAIL model simulations. The retrieved LAI is used
to improve wheat yield estimation, using assimilation methods based on
the Ensemble Kalman Filter, which assimilate the biophysical variables
into growth crop model. The second strategy estimates biomass from SAR
imagery. Polarimetric decomposition methods were used based on
multi-temporal fully polarimetric Radarsat-2 data during the entire
growing season. The estimated biomass was assimilating to FAO Aqua crop
model for improving the winter wheat yield estimation, with the Particle
Swarm Optimization (PSO) method. These procedures were used in a spatial
application with data collected in the rural area of Yangling (Shaanxi
Province) in 2014 and were validated for a number of wheat fields for
which ground yield data had been recorded and according to statistical
yield data for the area.Silvestro, P. C.: Comparison Between the Use of SAR and Optical Data for Wheat Yield Estimations Using Crop Model Assimilation
http://adsabs.harvard.edu/abs/2016ESASP.739E.109S
The aim of this work was to develop a tool to evaluate the effect of
water stress on yield losses at the farmland and regional scale, by
assimilating remotely sensed biophysical variables into crop growth
models. Biophysical variables were retrieved from HJ1A, HJ1B and Landsat
8 images, using an algorithm based on the training of artificial neural
networks on PROSAIL.For the assimilation, two crop models of differing
degree of complexity were used: Aquacrop and SAFY. For Aquacrop, an
optimization procedure to reduce the difference between the remotely
sensed and simulated CC was developed. For the modified version of SAFY,
the assimilation procedure was based on the Ensemble Kalman Filter.These
procedures were tested in a spatialized application, by using data
collected in the rural area of Yangling (Shaanxi Province) between 2013
and 2015Results were validated by utilizing yield data both from ground
measurements and statistical survey.Yang, G.: Spatialized Application of Remotely Sensed Data Assimilation Methods for Farmland Drought Monitoring Using Two Different Crop Models
http://adsabs.harvard.edu/abs/2016ESASP.739E.108Y
Drought is the most costly natural disasters in China and all over the
world. It is very important to evaluate the drought-induced crop yield
losses and further improve water use efficiency at regional scale.
Firstly, crop biomass was estimated by the combined use of Synthetic
Aperture Radar (SAR) and optical remote sensing data. Then the estimated
biophysical variable was assimilated into crop growth model (FAO
AquaCrop) by the Particle Swarm Optimization (PSO) method from farmland
scale to regional scale.At farmland scale, the most important crop
parameters of AquaCrop model were determined to reduce the used
parameters in assimilation procedure. The Extended Fourier Amplitude
Sensitivity Test (EFAST) method was used for assessing the contribution
of different crop parameters to model output. Moreover, the AquaCrop
model was calibrated using the experiment data in Xiaotangshan,
Beijing.At regional scale, spatial application of our methods were
carried out and validated in the rural area of Yangling, Shaanxi
Province, in 2014. This study will provide guideline to make irrigation
decision of balancing of water consumption and yield loss.Chu, T.: On the accuracy and precision of numerical waveforms: effect of waveform extraction methodology
http://adsabs.harvard.edu/abs/2016CQGra..33p5001C
We present a new set of 95 numerical relativity simulations of
non-precessing binary black holes (BBHs). The simulations sample
comprehensively both black-hole spins up to spin magnitude of 0.9, and
cover mass ratios 1-3. The simulations cover on average 24
inspiral orbits, plus merger and ringdown, with low initial orbital
eccentricities e\lt {10}<SUP>-4</SUP>. A subset of the simulations
extends the coverage of non-spinning BBHs up to mass ratio q = 10.
Gravitational waveforms at asymptotic infinity are computed with two
independent techniques: extrapolation and Cauchy characteristic
extraction. An error analysis based on noise-weighted inner products is
performed. We find that numerical truncation error, error due to
gravitational wave extraction, and errors due to the Fourier
transformation of signals with finite length of the numerical waveforms
are of similar magnitude, with gravitational wave extraction errors
dominating at noise-weighted mismatches of ˜ 3×
{10}<SUP>-4</SUP>. This set of waveforms will serve to validate and
improve aligned-spin waveform models for gravitational wave science.Planck Collaboration: Planck 2015 results. XXVIII. The Planck Catalogue of Galactic cold clumps
http://adsabs.harvard.edu/abs/2016A%26A...594A..28P
We present the Planck Catalogue of Galactic Cold Clumps (PGCC), an
all-sky catalogue of Galactic cold clump candidates detected by Planck.
This catalogue is the full version of the Early Cold Core (ECC)
catalogue, which was made available in 2011 with the Early Release
Compact Source Catalogue (ERCSC) and which contained 915 high
signal-to-noise sources. It is based on the Planck 48-month mission data
that are currently being released to the astronomical community. The
PGCC catalogue is an observational catalogue consisting exclusively of
Galactic cold sources. The three highest Planck bands (857, 454, and 353
GHz) have been combined with IRAS data at 3 THz to perform a
multi-frequency detection of sources colder than their local
environment. After rejection of possible extragalactic contaminants, the
PGCC catalogue contains 13188 Galactic sources spread across the whole
sky, i.e., from the Galactic plane to high latitudes, following the
spatial distribution of the main molecular cloud complexes. The median
temperature of PGCC sources lies between 13 and 14.5 K, depending on the
quality of the flux density measurements, with a temperature ranging
from 5.8 to 20 K after removing the sources with the top 1% highest
temperature estimates. Using seven independent methods, reliable
distance estimates have been obtained for 5574 sources, which allows us
to derive their physical properties such as their mass, physical size,
mean density, and luminosity.The PGCC sources are located mainly in the
solar neighbourhood, but also up to a distance of 10.5 kpc in the
direction of the Galactic centre, and range from low-mass cores to large
molecular clouds. Because of this diversity and because the PGCC
catalogue contains sources in very different environments, the catalogue
is useful for investigating the evolution from molecular clouds to
cores. Finally, it also includes 54 additional sources located in the
Small and Large Magellanic Clouds.Planck Collaboration: Planck 2015 results. XXIII. The thermal Sunyaev-Zeldovich effect-cosmic infrared background correlation
http://adsabs.harvard.edu/abs/2016A%26A...594A..23P
We use Planck data to detect the cross-correlation between the thermal
Sunyaev-Zeldovich (tSZ) effect and the infrared emission from the
galaxies that make up the the cosmic infrared background (CIB). We first
perform a stacking analysis towards Planck-confirmed galaxy clusters. We
detect infrared emission produced by dusty galaxies inside these
clusters and demonstrate that the infrared emission is about 50% more
extended than the tSZ effect. Modelling the emission with a
Navarro-Frenk-White profile, we find that the radial profile
concentration parameter is c<SUB>500</SUB> =
1.00<SUP>+0.18</SUP><SUB>-0.15</SUB> . This indicates that infrared
galaxies in the outskirts of clusters have higher infrared flux than
cluster-core galaxies. We also study the cross-correlation between tSZ
and CIB anisotropies, following three alternative approaches based on
power spectrum analyses: (i) using a catalogue of confirmed clusters
detected in Planck data; (ii) using an all-sky tSZ map built from Planck
frequency maps; and (iii) using cross-spectra between Planck frequency
maps. With the three different methods, we detect the tSZ-CIB
cross-power spectrum at significance levels of (i) 6σ; (ii)
3σ; and (iii) 4σ. We model the tSZ-CIB cross-correlation
signature and compare predictions with the measurements. The amplitude
of the cross-correlation relative to the fiducial model is
A<SUB>tSZ-CIB</SUB> = 1.2 ± 0.3. This result is consistent with
predictions for the tSZ-CIB cross-correlation assuming the best-fit
cosmological model from Planck 2015 results along with the tSZ and CIB
scaling relations.Planck Collaboration: Planck 2015 results. XIX. Constraints on primordial magnetic fields
http://adsabs.harvard.edu/abs/2016A%26A...594A..19P
We compute and investigate four types of imprint of a stochastic
background of primordial magnetic fields (PMFs) on the cosmic microwave
background (CMB) anisotropies: the impact of PMFs on the CMB temperature
and polarization spectra, which is related to their contribution to
cosmological perturbations; the effect on CMB polarization induced by
Faraday rotation; the impact of PMFs on the ionization history;
magnetically-induced non-Gaussianities and related non-zero bispectra;
and the magnetically-induced breaking of statistical isotropy. We
present constraints on the amplitude of PMFs that are derived from
different Planck data products, depending on the specific effect that is
being analysed. Overall, Planck data constrain the amplitude of PMFs to
less than a few nanoGauss, with different bounds that depend on the
considered model. In particular, individual limits coming from the
analysis of the CMB angular power spectra, using the Planck likelihood,
are B<SUB>1 Mpc</SUB> < 4.4 nG (where B<SUB>1 Mpc</SUB> is the
comoving field amplitude at a scale of 1 Mpc) at 95% confidence level,
assuming zero helicity. By considering the Planck likelihood, based only
on parity-even angular power spectra, we obtain B<SUB>1 Mpc</SUB> <
5.6 nG for a maximally helical field. For nearly scale-invariant PMFs we
obtain B<SUB>1 Mpc</SUB> < 2.0 nG and B<SUB>1 Mpc</SUB> < 0.9 nG
if the impact of PMFs on the ionization history of the Universe is
included in the analysis. From the analysis of magnetically-induced
non-Gaussianity, we obtain three different values, corresponding to
three applied methods, all below 5 nG. The constraint from the
magnetically-induced passive-tensor bispectrum is B<SUB>1 Mpc</SUB> <
2.8 nG. A search for preferred directions in the magnetically-induced
passive bispectrum yields B<SUB>1 Mpc</SUB> < 4.5 nG, whereas the
compensated-scalar bispectrum gives B<SUB>1 Mpc</SUB> < 3 nG. The
analysis of the Faraday rotation of CMB polarization by PMFs uses the
Planck power spectra in EE and BB at 70 GHz and gives B<SUB>1 Mpc</SUB>
< 1380 nG. In our final analysis, we consider the harmonic-space
correlations produced by Alfvén waves, finding no significant
evidence for the presence of these waves. Together, these results
comprise a comprehensive set of constraints on possible PMFs with Planck
data.Planck Collaboration: Planck 2015 results. XVI. Isotropy and statistics of the CMB
http://adsabs.harvard.edu/abs/2016A%26A...594A..16P
We test the statistical isotropy and Gaussianity of the cosmic microwave
background (CMB) anisotropies using observations made by the Planck
satellite. Our results are based mainly on the full Planck mission for
temperature, but also include some polarization measurements. In
particular, we consider the CMB anisotropy maps derived from the
multi-frequency Planck data by several component-separation methods. For
the temperature anisotropies, we find excellent agreement between
results based on these sky maps over both a very large fraction of the
sky and a broad range of angular scales, establishing that potential
foreground residuals do not affect our studies. Tests of skewness,
kurtosis, multi-normality, N-point functions, and Minkowski functionals
indicate consistency with Gaussianity, while a power deficit at large
angular scales is manifested in several ways, for example low map
variance. The results of a peak statistics analysis are consistent with
the expectations of a Gaussian random field. The "Cold Spot" is detected
with several methods, including map kurtosis, peak statistics, and mean
temperature profile. We thoroughly probe the large-scale dipolar power
asymmetry, detecting it with several independent tests, and address the
subject of a posteriori correction. Tests of directionality suggest the
presence of angular clustering from large to small scales, but at a
significance that is dependent on the details of the approach. We
perform the first examination of polarization data, finding the
morphology of stacked peaks to be consistent with the expectations of
statistically isotropic simulations. Where they overlap, these results
are consistent with the Planck 2013 analysis based on the nominal
mission data and provide our most thorough view of the statistics of the
CMB fluctuations to date.Planck Collaboration: Planck 2015 results. IX. Diffuse component separation: CMB maps
http://adsabs.harvard.edu/abs/2016A%26A...594A...9P
We present foreground-reduced cosmic microwave background (CMB) maps
derived from the full Planck data set in both temperature and
polarization. Compared to the corresponding Planck 2013 temperature sky
maps, the total data volume is larger by a factor of 3.2 for frequencies
between 30 and 70 GHz, and by 1.9 for frequencies between 100 and 857
GHz. In addition, systematic errors in the forms of
temperature-to-polarization leakage, analogue-to-digital conversion
uncertainties, and very long time constant errors have been dramatically
reduced, to the extent that the cosmological polarization signal may now
be robustly recovered on angular scales ℓ ≳ 40. On the very
largest scales, instrumental systematic residuals are still
non-negligible compared to the expected cosmological signal, and modes
with ℓ< 20 are accordingly suppressed in the current polarization
maps by high-pass filtering. As in 2013, four different CMB component
separation algorithms are applied to these observations, providing a
measure of stability with respect to algorithmic and modelling choices.
The resulting polarization maps have rms instrumental noise ranging
between 0.21 and 0.27μK averaged over 55' pixels, and between 4.5 and
6.1μK averaged over 3.4 parcm pixels. The cosmological parameters
derived from the analysis of temperature power spectra are in agreement
at the 1σ level with the Planck 2015 likelihood. Unresolved
mismatches between the noise properties of the data and simulations
prevent a satisfactory description of the higher-order statistical
properties of the polarization maps. Thus, the primary applications of
these polarization maps are those that do not require massive
simulations for accurate estimation of uncertainties, for instance
estimation of cross-spectra and cross-correlations, or stacking
analyses. However, the amplitude of primordial non-Gaussianity is
consistent with zero within 2σ for all local, equilateral, and
orthogonal configurations of the bispectrum, including for polarization
E-modes. Moreover, excellent agreement is found regarding the lensing
B-mode power spectrum, both internally among the various component
separation codes and with the best-fit Planck 2015 Λ cold dark
matter model.Planck Collaboration: Planck 2015 results. VIII. High Frequency Instrument data processing: Calibration and maps
http://adsabs.harvard.edu/abs/2016A%26A...594A...8P
This paper describes the processing applied to the cleaned, time-ordered
information obtained from the Planck High Frequency Instrument (HFI)
with the aim of producing photometrically calibrated maps in temperature
and (for the first time) in polarization. The data from the entire
2.5-year HFI mission include almost five full-sky surveys. HFI observes
the sky over a broad range of frequencies, from 100 to 857 GHz. To
obtain the best accuracy on the calibration over such a large range, two
different photometric calibration schemes have been used. The 545 and
857 GHz data are calibrated using models of planetary atmospheric
emission. The lower frequencies (from 100 to 353 GHz) are calibrated
using the time-variable cosmological microwave background dipole, which
we call the orbital dipole. This source of calibration only depends on
the satellite velocity with respect to the solar system. Using a CMB
temperature of T<SUB>CMB</SUB> = 2.7255 ± 0.0006 K, it permits an
independent measurement of the amplitude of the CMB solar dipole (3364.3
± 1.5 μK), which is approximatively 1σ higher than the
WMAP measurement with a direction that is consistent between the two
experiments. We describe the pipeline used to produce the maps
ofintensity and linear polarization from the HFI timelines, and the
scheme used to set the zero level of the maps a posteriori. We also
summarize the noise characteristics of the HFI maps in the 2015 Planck
data release and present some null tests to assess their quality.
Finally, we discuss the major systematic effects and in particular the
leakage induced by flux mismatch between the detectors that leads to
spurious polarization signal.Planck Collaboration: Planck 2015 results. V. LFI calibration
http://adsabs.harvard.edu/abs/2016A%26A...594A...5P
We present a description of the pipeline used to calibrate the Planck
Low Frequency Instrument (LFI) timelines into thermodynamic temperatures
for the Planck 2015 data release, covering four years of uninterrupted
operations. As in the 2013 data release, our calibrator is provided by
the spin-synchronous modulation of the cosmic microwave background
dipole, but we now use the orbital component, rather than adopting the
Wilkinson Microwave Anisotropy Probe (WMAP) solar dipole. This allows
our 2015 LFI analysis to provide an independent Solar dipole estimate,
which is in excellent agreement with that of HFI and within 1σ
(0.3% in amplitude) of the WMAP value. This 0.3% shift in the
peak-to-peak dipole temperature from WMAP and a general overhaul of the
iterative calibration code increases the overall level of the LFI maps
by 0.45% (30 GHz), 0.64% (44 GHz), and 0.82% (70 GHz) in temperature
with respect to the 2013 Planck data release, thus reducing the
discrepancy with the power spectrum measured by WMAP. We estimate that
the LFI calibration uncertainty is now at the level of 0.20% for the 70
GHz map, 0.26% for the 44 GHz map, and 0.35% for the 30 GHz map. We
provide a detailed description of the impact of all the changes
implemented in the calibration since the previous data release.Planck Collaboration: Planck 2015 results. IV. Low Frequency Instrument beams and window functions
http://adsabs.harvard.edu/abs/2016A%26A...594A...4P
This paper presents the characterization of the in-flight beams, the
beam window functions, and the associated uncertainties for the Planck
Low Frequency Instrument (LFI). The structure of the paper is similar to
that presented in the 2013 Planck release; the main differences concern
the beam normalization and the delivery of the window functions to be
used for polarization analysis. The in-flight assessment of the LFI main
beams relies on measurements performed during observations of Jupiter.
By stacking data from seven Jupiter transits, the main beam profiles are
measured down to -25 dB at 30 and 44 GHz, and down to -30 dB at 70 GHz.
It has been confirmed that the agreement between the simulated beams and
the measured beams is better than 1% at each LFI frequency band (within
the 20 dB contour from the peak, the rms values are 0.1% at 30 and 70
GHz; 0.2% at 44 GHz). Simulated polarized beams are used for the
computation of the effective beam window functions. The error budget for
the window functions is estimated from both main beam and sidelobe
contributions, and accounts for the radiometer band shapes. The total
uncertainties in the effective beam window functions are 0.7% and 1% at
30 and 44 GHz, respectively (at ℓ ≈ 600); and 0.5% at 70 GHz (at
ℓ ≈ 1000).Planck Collaboration: Planck 2015 results. III. LFI systematic uncertainties
http://adsabs.harvard.edu/abs/2016A%26A...594A...3P
We present the current accounting of systematic effect uncertainties for
the Low Frequency Instrument (LFI) that are relevant to the 2015 release
of the Planck cosmological results, showing the robustness and
consistency of our data set, especially for polarization analysis. We
use two complementary approaches: (i) simulations based on measured data
and physical models of the known systematic effects; and (ii) analysis
of difference maps containing the same sky signal ("null-maps"). The LFI
temperature data are limited by instrumental noise. At large angular
scales the systematic effects are below the cosmic microwave background
(CMB) temperature power spectrum by several orders of magnitude. In
polarization the systematic uncertainties are dominated by calibration
uncertainties and compete with the CMB E-modes in the multipole range
10-20. Based on our model of all known systematic effects, we show that
these effects introduce a slight bias of around 0.2σ on the
reionization optical depth derived from the 70GHz EE spectrum using the
30 and 353GHz channels as foreground templates. At 30GHz the systematic
effects are smaller than the Galactic foreground at all scales in
temperature and polarization, which allows us to consider this channel
as a reliable template of synchrotron emission. We assess the residual
uncertainties due to LFI effects on CMB maps and power spectra after
component separation and show that these effects are smaller than the
CMB amplitude at all scales. We also assess the impact on
non-Gaussianity studies and find it to be negligible. Some residuals
still appear in null maps from particular sky survey pairs, particularly
at 30 GHz, suggesting possible straylight contamination due to an
imperfect knowledge of the beam far sidelobes.Hubmayr, J.: Design of 280 GHz feedhorn-coupled TES arrays for the balloon-borne polarimeter SPIDER
http://adsabs.harvard.edu/abs/2016SPIE.9914E..0VH
We describe 280 GHz bolometric detector arrays that instrument the
balloon-borne polarimeter spider. A primary science goal of spider is to
measure the large-scale B-mode polarization of the cosmic microwave
background (cmb) in search of the cosmic-inflation, gravitational-wave
signature. 280 GHz channels aid this science goal by constraining the
level of B-mode contamination from galactic dust emission. We present
the focal plane unit design, which consists of a 16x16 array of conical,
corrugated feedhorns coupled to a monolithic detector array fabricated
on a 150 mm diameter silicon wafer. Detector arrays are capable of
polarimetric sensing via waveguide probe-coupling to a multiplexed array
of transition-edge-sensor (TES) bolometers. The spider receiver has
three focal plane units at 280 GHz, which in total contains 765 spatial
pixels and 1,530 polarization sensitive bolometers. By fabrication and
measurement of single feedhorns, we demonstrate 14.7° FHWM
Gaussian-shaped beams with <1% ellipticity in a 30% fractional
bandwidth centered at 280 GHz. We present electromagnetic simulations of
the detection circuit, which show 94% band-averaged, single-polarization
coupling efficiency, 3% reflection and 3% radiative loss. Lastly, we
demonstrate a low thermal conductance bolometer, which is well-described
by a simple TES model and exhibits an electrical noise equivalent power
(NEP) = 2.6 x 10<SUP>-17</SUP> W/√Hz, consistent with the phonon
noise prediction.De Bernardis, F.: Survey strategy optimization for the Atacama Cosmology Telescope
http://adsabs.harvard.edu/abs/2016SPIE.9910E..14D
In recent years there have been significant improvements in the
sensitivity and the angular resolution of the instruments dedicated to
the observation of the Cosmic Microwave Background (CMB). ACTPol is the
first polarization receiver for the Atacama Cosmology Telescope (ACT)
and is observing the CMB sky with arcmin resolution over 2000 sq. deg.
Its upgrade, Advanced ACTPol (AdvACT), will observe the CMB in five
frequency bands and over a larger area of the sky. We describe the
optimization and implementation of the ACTPol and AdvACT surveys. The
selection of the observed fields is driven mainly by the science goals,
that is, small angular scale CMB measurements, B-mode measurements and
cross-correlation studies. For the ACTPol survey we have observed
patches of the southern galactic sky with low galactic foreground
emissions which were also chosen to maximize the overlap with several
galaxy surveys to allow unique cross-correlation studies. A wider field
in the northern galactic cap ensured significant additional overlap with
the BOSS spectroscopic survey. The exact shapes and footprints of the
fields were optimized to achieve uniform coverage and to obtain
cross-linked maps by observing the fields with different scan
directions. We have maximized the efficiency of the survey by
implementing a close to 24 hour observing strategy, switching between
daytime and nighttime observing plans and minimizing the telescope idle
time. We describe the challenges represented by the survey optimization
for the significantly wider area observed by AdvACT, which will observe
roughly half of the low-foreground sky. The survey strategies described
here may prove useful for planning future ground-based CMB surveys, such
as the Simons Observatory and CMB Stage IV surveys.D'Orazio, D. J.: Bright transients from strongly-magnetized neutron star-black hole mergers
http://adsabs.harvard.edu/abs/2016PhRvD..94b3001D
Direct detection of black hole-neutron star pairs is anticipated with
the advent of aLIGO. Electromagnetic counterparts may be crucial for a
confident gravitational-wave detection as well as for extraction of
astronomical information. Yet black hole-neutron star pairs are
notoriously dark and so inaccessible to telescopes. Contrary to this
expectation, a bright electromagnetic transient can occur in the final
moments before merger as long as the neutron star is highly magnetized.
The orbital motion of the neutron star magnet creates a Faraday flux and
corresponding power available for luminosity. A spectrum of curvature
radiation ramps up until the rapid injection of energy ignites a
fireball, which would appear as an energetic blackbody peaking in the x
ray to γ rays for neutron star field strengths ranging from
10<SUP>12</SUP> to 10<SUP>16</SUP> G respectively and a 10
M<SUB>⊙</SUB> black hole. The fireball event may last from a few
milliseconds to a few seconds depending on the neutron star
magnetic-field strength, and may be observable with the Fermi Gamma-Ray
Burst Monitor with a rate up to a few per year for neutron star field
strengths ≳10<SUP>14</SUP> G . We also discuss a possible decaying
post-merger event which could accompany this signal. As an
electromagnetic counterpart to these otherwise dark pairs, the
black-hole battery should be of great value to the development of
multi-messenger astronomy in the era of aLIGO.Connor, L.: Constraints on the FRB rate at 700-900 MHz
http://adsabs.harvard.edu/abs/2016MNRAS.460.1054C
Estimating the all-sky rate of fast radio bursts (FRBs) has been
difficult due to small-number statistics and the fact that they are seen
by disparate surveys in different regions of the sky. In this paper we
provide limits for the FRB rate at 800 MHz based on the only burst
detected at frequencies below 1.4 GHz, FRB 110523. We discuss the
difficulties in rate estimation, particularly in providing an all-sky
rate above a single fluence threshold. We find an implied rate between
700 and 900 MHz that is consistent with the rate at 1.4 GHz, scaling to
6.4^{+29.5}_{-5.0} × 10^3 sky<SUP>-1</SUP> d<SUP>-1</SUP> for an
HTRU-like survey. This is promising for upcoming experiments below a GHz
like CHIME and UTMOST, for which we forecast detection rates. Given
110523's discovery at 32σ with nothing weaker detected, down to
the threshold of 8σ, we find consistency with a Euclidean flux
distribution but disfavour steep distributions, ruling out γ >
2.2.Knowles, K.: A giant radio halo in a low-mass SZ-selected galaxy cluster: ACT-CL J0256.5+0006
http://adsabs.harvard.edu/abs/2016MNRAS.459.4240K
We present the detection of a giant radio halo (GRH) in the
Sunyaev-Zel'dovich (SZ)-selected merging galaxy cluster ACT-CL
J0256.5+0006 (z = 0.363), observed with the Giant Metrewave Radio
Telescope at 325 and 610 MHz. We find this cluster to host a faint
(S<SUB>610</SUB> = 5.6 ± 1.4 mJy) radio halo with an angular
extent of 2.6 arcmin, corresponding to 0.8 Mpc at the cluster redshift,
qualifying it as a GRH. J0256 is one of the lowest mass systems,
M<SUB>500, SZ</SUB> = (5.0 ± 1.2) × 10<SUP>14</SUP>
M<SUB>⊙</SUB>, found to host a GRH. We measure the GRH at lower
significance at 325 MHz (S<SUB>325</SUB> = 10.3 ± 5.3 mJy),
obtaining a spectral index measurement of α ^{610}_{325} =
1.0^{+0.7}_{-0.9}. This result is consistent with the mean spectral
index of the population of typical radio haloes, α = 1.2 ±
0.2. Adopting the latter value, we determine a 1.4 GHz radio power of
P<SUB>1.4 GHz</SUB> = (1.0 ± 0.3) × 10<SUP>24</SUP> W
Hz<SUP>-1</SUP>, placing this cluster within the scatter of known
scaling relations. Various lines of evidence, including the intracluster
medium morphology, suggest that ACT-CL J0256.5+0006 is composed of two
subclusters. We determine a merger mass ratio of 7:4, and a
line-of-sight velocity difference of v<SUB>⊥</SUB> = 1880 ±
210 km s<SUP>-1</SUP>. We construct a simple merger model to infer
relevant time-scales in the merger. From its location on the P<SUB>1.4
GHz</SUB>-L<SUB>X</SUB> scaling relation, we infer that we observe
ACT-CL J0256.5+0006 just before first core crossing.Ma, X.: Binary stars can provide the `missing photons' needed for reionization
http://adsabs.harvard.edu/abs/2016MNRAS.459.3614M
Empirical constraints on reionization require galactic ionizing photon
escape fractions f<SUB>esc</SUB> ≳ 20 per cent, but recent
high-resolution radiation-hydrodynamic calculations have consistently
found much lower values ˜1-5 per cent. While these models include
strong stellar feedback and additional processes such as runaway stars,
they almost exclusively consider stellar evolution models based on
single (isolated) stars, despite the fact that most massive stars are in
binaries. We re-visit these calculations, combining radiative transfer
and high-resolution cosmological simulations with detailed models for
stellar feedback from the Feedback in Realistic Environments project.
For the first time, we use a stellar evolution model that includes a
physically and observationally motivated treatment of binaries (the
Binary Population and Spectral Synthesis model). Binary mass transfer
and mergers enhance the population of massive stars at late times
(≳3 Myr) after star formation, which in turn strongly enhances the
late-time ionizing photon production (especially at low metallicities).
These photons are produced after feedback from massive stars has carved
escape channels in the interstellar medium, and so efficiently leak out
of galaxies. As a result, the time-averaged `effective' escape fraction
(ratio of escaped ionizing photons to observed 1500 Å photons)
increases by factors ˜4-10, sufficient to explain reionization.
While important uncertainties remain, we conclude that binary evolution
may be critical for understanding the ionization of the Universe.Rein, H.: Second-order variational equations for N-body simulations
http://adsabs.harvard.edu/abs/2016MNRAS.459.2275R
First-order variational equations are widely used in N-body simulations
to study how nearby trajectories diverge from one another. These allow
for efficient and reliable determinations of chaos indicators such as
the Maximal Lyapunov characteristic Exponent (MLE) and the Mean
Exponential Growth factor of Nearby Orbits (MEGNO). In this paper we lay
out the theoretical framework to extend the idea of variational
equations to higher order. We explicitly derive the differential
equations that govern the evolution of second-order variations in the
N-body problem. Going to second order opens the door to new
applications, including optimization algorithms that require the first
and second derivatives of the solution, like the classical Newton's
method. Typically, these methods have faster convergence rates than
derivative-free methods. Derivatives are also required for Riemann
manifold Langevin and Hamiltonian Monte Carlo methods which provide
significantly shorter correlation times than standard methods. Such
improved optimization methods can be applied to anything from
radial-velocity/transit-timing-variation fitting to spacecraft
trajectory optimization to asteroid deflection. We provide an
implementation of first- and second-order variational equations for the
publicly available REBOUND integrator package. Our implementation allows
the simultaneous integration of any number of first- and second-order
variational equations with the high-accuracy IAS15 integrator. We also
provide routines to generate consistent and accurate initial conditions
without the need for finite differencing.Abbott, B. P.: Characterization of transient noise in Advanced LIGO relevant to gravitational wave signal GW150914
http://adsabs.harvard.edu/abs/2016CQGra..33m4001A
On 14 September 2015, a gravitational wave signal from a coalescing
black hole binary system was observed by the Advanced LIGO detectors.
This paper describes the transient noise backgrounds used to determine
the significance of the event (designated GW150914) and presents the
results of investigations into potential correlated or uncorrelated
sources of transient noise in the detectors around the time of the
event. The detectors were operating nominally at the time of GW150914.
We have ruled out environmental influences and non-Gaussian instrument
noise at either LIGO detector as the cause of the observed gravitational
wave signal.Abbott, B. P.: Supplement: "Localization and Broadband Follow-up of the Gravitational-wave Transient GW150914" (2016, ApJL, 826, L13)
http://adsabs.harvard.edu/abs/2016ApJS..225....8A
This Supplement provides supporting material for Abbott et al. (2016a).
We briefly summarize past electromagnetic (EM) follow-up efforts as well
as the organization and policy of the current EM follow-up program. We
compare the four probability sky maps produced for the
gravitational-wave transient GW150914, and provide additional details of
the EM follow-up observations that were performed in the different
bands.Abbott, B. P.: Localization and Broadband Follow-up of the Gravitational-wave Transient GW150914
http://adsabs.harvard.edu/abs/2016ApJ...826L..13A
A gravitational-wave (GW) transient was identified in data recorded by
the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)
detectors on 2015 September 14. The event, initially designated G184098
and later given the name GW150914, is described in detail elsewhere. By
prior arrangement, preliminary estimates of the time, significance, and
sky location of the event were shared with 63 teams of observers
covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths
with ground- and space-based facilities. In this Letter we describe the
low-latency analysis of the GW data and present the sky localization of
the first observed compact binary merger. We summarize the follow-up
observations reported by 25 teams via private Gamma-ray Coordinates
Network circulars, giving an overview of the participating facilities,
the GW sky localization coverage, the timeline, and depth of the
observations. As this event turned out to be a binary black hole merger,
there is little expectation of a detectable electromagnetic (EM)
signature. Nevertheless, this first broadband campaign to search for a
counterpart of an Advanced LIGO source represents a milestone and
highlights the broad capabilities of the transient astronomy community
and the observing strategies that have been developed to pursue neutron
star binary merger events. Detailed investigations of the EM data and
results of the EM follow-up campaign are being disseminated in papers by
the individual teams.Farr, B.: Parameter Estimation on Gravitational Waves from Neutron-star Binaries with Spinning Components
http://adsabs.harvard.edu/abs/2016ApJ...825..116F
Inspiraling binary neutron stars (BNSs) are expected to be one of the
most significant sources of gravitational-wave signals for the new
generation of advanced ground-based detectors. We investigate how well
we could hope to measure properties of these binaries using the Advanced
LIGO detectors, which began operation in September 2015. We study an
astrophysically motivated population of sources (binary components with
masses 1.2\quad {M}<SUB>⊙ </SUB>{--}1.6\quad {M}<SUB>⊙ </SUB>
and spins of less than 0.05) using the full LIGO analysis pipeline.
While this simulated population covers the observed range of potential
BNS sources, we do not exclude the possibility of sources with
parameters outside these ranges; given the existing uncertainty in
distributions of mass and spin, it is critical that analyses account for
the full range of possible mass and spin configurations. We find that
conservative prior assumptions on neutron-star mass and spin lead to
average fractional uncertainties in component masses of ˜16%, with
little constraint on spins (the median 90% upper limit on the spin of
the more massive component is ˜0.7). Stronger prior constraints on
neutron-star spins can further constrain mass estimates but only
marginally. However, we find that the sky position and luminosity
distance for these sources are not influenced by the inclusion of spin;
therefore, if LIGO detects a low-spin population of BNS sources, less
computationally expensive results calculated neglecting spin will be
sufficient for guiding electromagnetic follow-up.Molinari, S.: Hi-GAL, the Herschel infrared Galactic Plane Survey: photometric maps and compact source catalogues. First data release for the inner Milky Way: +68° ≥ l ≥ -70°
http://adsabs.harvard.edu/abs/2016A%26A...591A.149M
<BR /> Aims: We present the first public release of high-quality data
products (DR1) from Hi-GAL, the Herschel infrared Galactic Plane Survey.
Hi-GAL is the keystone of a suite of continuum Galactic plane surveys
from the near-IR to the radio and covers five wavebands at 70, 160, 250,
350 and 500 μm, encompassing the peak of the spectral energy
distribution of cold dust for 8 ≲ T ≲ 50 K. This first Hi-GAL
data release covers the inner Milky Way in the longitude range 68°
≳ ℓ ≳ -70° in a | b | ≤ 1° latitude strip. <BR
/> Methods: Photometric maps have been produced with the ROMAGAL
pipeline, which optimally capitalizes on the excellent sensitivity and
stability of the bolometer arrays of the Herschel PACS and SPIRE
photometric cameras. It delivers images of exquisite quality and
dynamical range, absolutely calibrated with Planck and IRAS, and
recovers extended emission at all wavelengths and all spatial scales,
from the point-spread function to the size of an entire 2°×
2° "tile" that is the unit observing block of the survey. The
compact source catalogues were generated with the CuTEx algorithm, which
was specifically developed to optimise source detection and extraction
in the extreme conditions of intense and spatially varying background
that are found in the Galactic plane in the thermal infrared. <BR />
Results: Hi-GAL DR1 images are cirrus noise limited and reach the
1σ-rms predicted by the Herschel Time Estimators for parallel-mode
observations at 60'' s<SUP>-1</SUP> scanning speed in relatively low
cirrus emission regions. Hi-GAL DR1 images will be accessible through a
dedicated web-based image cutout service. The DR1 Compact Source
Catalogues are delivered as single-band photometric lists containing, in
addition to source position, peak, and integrated flux and source sizes,
a variety of parameters useful to assess the quality and reliability of
the extracted sources. Caveats and hints to help in this assessment are
provided. Flux completeness limits in all bands are determined from
extensive synthetic source experiments and greatly depend on the
specific line of sight along the Galactic plane because the background
strongly varies as a function of Galactic longitude. Hi-GAL DR1
catalogues contain 123210, 308509, 280685, 160972, and 85460 compact
sources in the five bands.
Herschel is an ESA space observatory with science instruments provided
by European-led Principal Investigator consortia and with important
participation from NASA.The images and the catalogues are only available
at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A
href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A149">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A149</A>Abbott, B. P.: GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence
http://adsabs.harvard.edu/abs/2016PhRvL.116x1103A
We report the observation of a gravitational-wave signal produced by the
coalescence of two stellar-mass black holes. The signal, GW151226, was
observed by the twin detectors of the Laser Interferometer
Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53
UTC. The signal was initially identified within 70 s by an online
matched-filter search targeting binary coalescences. Subsequent off-line
analyses recovered GW151226 with a network signal-to-noise ratio of 13
and a significance greater than 5 σ . The signal persisted in the
LIGO frequency band for approximately 1 s, increasing in frequency and
amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak
gravitational strain of 3.
4<SUB>-0.9</SUB><SUP>+0.7</SUP>×10<SUP>-22</SUP> . The inferred
source-frame initial black hole masses are
14.2<SUB>-3.7</SUB><SUP>+8.3</SUP> M<SUB>⊙</SUB> and 7.
5<SUB>-2.3</SUB><SUP>+2.3</SUP> M<SUB>⊙</SUB>, and the final black
hole mass is 20.8<SUB>-1.7</SUB><SUP>+6.1</SUP> M<SUB>⊙</SUB>. We
find that at least one of the component black holes has spin greater
than 0.2. This source is located at a luminosity distance of 44
0<SUB>-190</SUB><SUP>+180</SUP> Mpc corresponding to a redshift of 0.0
9<SUB>-0.04</SUB><SUP>+0.03</SUP>. All uncertainties define a 90%
credible interval. This second gravitational-wave observation provides
improved constraints on stellar populations and on deviations from
general relativity.Abbott, B. P.: Properties of the Binary Black Hole Merger GW150914
http://adsabs.harvard.edu/abs/2016PhRvL.116x1102A
On September 14, 2015, the Laser Interferometer Gravitational-Wave
Observatory (LIGO) detected a gravitational-wave transient (GW150914);
we characterize the properties of the source and its parameters. The
data around the time of the event were analyzed coherently across the
LIGO network using a suite of accurate waveform models that describe
gravitational waves from a compact binary system in general relativity.
GW150914 was produced by a nearly equal mass binary black hole of masses
3 6<SUB>-4</SUB><SUP>+5</SUP>M<SUB>⊙</SUB> and 2
9<SUB>-4</SUB><SUP>+4</SUP>M<SUB>⊙</SUB> ; for each parameter we
report the median value and the range of the 90% credible interval. The
dimensionless spin magnitude of the more massive black hole is bound to
be <0.7 (at 90% probability). The luminosity distance to the source
is 41 0<SUB>-180</SUB><SUP>+160</SUP> Mpc , corresponding to a redshift
0.0 9<SUB>-0.04</SUB><SUP>+0.03</SUP> assuming standard cosmology. The
source location is constrained to an annulus section of 610
deg<SUP>2</SUP> , primarily in the southern hemisphere. The binary
merges into a black hole of mass 6
2<SUB>-4</SUB><SUP>+4</SUP>M<SUB>⊙</SUB> and spin 0.6
7<SUB>-0.07</SUB><SUP>+0.05</SUP>. This black hole is significantly more
massive than any other inferred from electromagnetic observations in the
stellar-mass regime.Abbott, B. P.: Tests of General Relativity with GW150914
http://adsabs.harvard.edu/abs/2016PhRvL.116v1101A
The LIGO detection of GW150914 provides an unprecedented opportunity to
study the two-body motion of a compact-object binary in the
large-velocity, highly nonlinear regime, and to witness the final merger
of the binary and the excitation of uniquely relativistic modes of the
gravitational field. We carry out several investigations to determine
whether GW150914 is consistent with a binary black-hole merger in
general relativity. We find that the final remnant's mass and spin, as
determined from the low-frequency (inspiral) and high-frequency
(postinspiral) phases of the signal, are mutually consistent with the
binary black-hole solution in general relativity. Furthermore, the data
following the peak of GW150914 are consistent with the least-damped
quasinormal mode inferred from the mass and spin of the remnant black
hole. By using waveform models that allow for parametrized
general-relativity violations during the inspiral and merger phases, we
perform quantitative tests on the gravitational-wave phase in the
dynamical regime and we determine the first empirical bounds on several
high-order post-Newtonian coefficients. We constrain the graviton
Compton wavelength, assuming that gravitons are dispersed in vacuum in
the same way as particles with mass, obtaining a 90%-confidence lower
bound of 10<SUP>13</SUP> km . In conclusion, within our statistical
uncertainties, we find no evidence for violations of general relativity
in the genuinely strong-field regime of gravity.Meerburg, P. D.: CMB B -mode non-Gaussianity
http://adsabs.harvard.edu/abs/2016PhRvD..93l3511M
We study the degree to which the cosmic microwave background (CMB) can
be used to constrain primordial non-Gaussianity involving one tensor and
two scalar fluctuations, focusing on the correlation of one polarization
B mode with two temperature modes. In the simplest models of inflation,
the tensor-scalar-scalar primordial bispectrum is nonvanishing and is of
the same order in slow-roll parameters as the scalar-scalar-scalar
bispectrum. We calculate the ⟨B T T ⟩ correlation arising from
a primordial tensor-scalar-scalar bispectrum, and show that constraints
from an experiment like CMB-Stage IV using this observable are more than
an order of magnitude better than those on the same primordial coupling
obtained from temperature measurements alone. We argue that B -mode
non-Gaussianity opens up an as-yet-unexplored window into the early
Universe, demonstrating that significant information on primordial
physics remains to be harvested from CMB anisotropies.Adrián-Martínez, S.: High-energy neutrino follow-up search of gravitational wave event GW150914 with ANTARES and IceCube
http://adsabs.harvard.edu/abs/2016PhRvD..93l2010A
We present the high-energy-neutrino follow-up observations of the first
gravitational wave transient GW150914 observed by the Advanced LIGO
detectors on September 14, 2015. We search for coincident neutrino
candidates within the data recorded by the IceCube and Antares neutrino
detectors. A possible joint detection could be used in targeted
electromagnetic follow-up observations, given the significantly better
angular resolution of neutrino events compared to gravitational waves.
We find no neutrino candidates in both temporal and spatial coincidence
with the gravitational wave event. Within ±500 s of the
gravitational wave event, the number of neutrino candidates detected by
IceCube and Antares were three and zero, respectively. This is
consistent with the expected atmospheric background, and none of the
neutrino candidates were directionally coincident with GW150914. We use
this nondetection to constrain neutrino emission from the
gravitational-wave event.Abbott, B. P.: Search for transient gravitational waves in coincidence with short-duration radio transients during 2007-2013
http://adsabs.harvard.edu/abs/2016PhRvD..93l2008A
We present an archival search for transient gravitational-wave bursts in
coincidence with 27 single-pulse triggers from Green Bank Telescope
pulsar surveys, using the LIGO, Virgo, and GEO interferometer network.
We also discuss a check for gravitational-wave signals in coincidence
with Parkes fast radio bursts using similar methods. Data analyzed in
these searches were collected between 2007 and 2013. Possible sources of
emission of both short-duration radio signals and transient
gravitational-wave emission include starquakes on neutron stars, binary
coalescence of neutron stars, and cosmic string cusps. While no evidence
for gravitational-wave emission in coincidence with these radio
transients was found, the current analysis serves as a prototype for
similar future searches using more sensitive second-generation
interferometers.Abbott, B. P.: Observing gravitational-wave transient GW150914 with minimal assumptions
http://adsabs.harvard.edu/abs/2016PhRvD..93l2004A
The gravitational-wave signal GW150914 was first identified on September
14, 2015, by searches for short-duration gravitational-wave transients.
These searches identify time-correlated transients in multiple detectors
with minimal assumptions about the signal morphology, allowing them to
be sensitive to gravitational waves emitted by a wide range of sources
including binary black hole mergers. Over the observational period from
September 12 to October 20, 2015, these transient searches were
sensitive to binary black hole mergers similar to GW150914 to an average
distance of ˜600 Mpc . In this paper, we describe the analyses
that first detected GW150914 as well as the parameter estimation and
waveform reconstruction techniques that initially identified GW150914 as
the merger of two black holes. We find that the reconstructed waveform
is consistent with the signal from a binary black hole merger with a
chirp mass of ˜30 M<SUB>⊙</SUB> and a total mass before merger
of ˜70 M<SUB>⊙</SUB> in the detector frame.Abbott, B. P.: GW150914: First results from the search for binary black hole coalescence with Advanced LIGO
http://adsabs.harvard.edu/abs/2016PhRvD..93l2003A
On September 14, 2015, at 09∶50:45 UTC the two detectors of the
Laser Interferometer Gravitational-Wave Observatory (LIGO)
simultaneously observed the binary black hole merger GW150914. We report
the results of a matched-filter search using relativistic models of
compact-object binaries that recovered GW150914 as the most significant
event during the coincident observations between the two LIGO detectors
from September 12 to October 20, 2015 GW150914 was observed with a
matched-filter signal-to-noise ratio of 24 and a false alarm rate
estimated to be less than 1 event per 203000 years, equivalent to a
significance greater than 5.1 σ .Mead, A. J.: Accurate halo-model matter power spectra with dark energy, massive neutrinos and modified gravitational forces
http://adsabs.harvard.edu/abs/2016MNRAS.459.1468M
We present an accurate non-linear matter power spectrum prediction
scheme for a variety of extensions to the standard cosmological
paradigm, which uses the tuned halo model previously developed in Mead
et al. We consider dark energy models that are both minimally and
non-minimally coupled, massive neutrinos and modified gravitational
forces with chameleon and Vainshtein screening mechanisms. In all cases,
we compare halo-model power spectra to measurements from high-resolution
simulations. We show that the tuned halo-model method can predict the
non-linear matter power spectrum measured from simulations of
parametrized w(a) dark energy models at the few per cent level for k
< 10 h Mpc<SUP>-1</SUP>, and we present theoretically motivated
extensions to cover non-minimally coupled scalar fields, massive
neutrinos and Vainshtein screened modified gravity models that result in
few per cent accurate power spectra for k < 10 h Mpc<SUP>-1</SUP>.
For chameleon screened models, we achieve only 10 per cent accuracy for
the same range of scales. Finally, we use our halo model to investigate
degeneracies between different extensions to the standard cosmological
model, finding that the impact of baryonic feedback on the non-linear
matter power spectrum can be considered independently of modified
gravity or massive neutrino extensions. In contrast, considering the
impact of modified gravity and massive neutrinos independently results
in biased estimates of power at the level of 5 per cent at scales k >
0.5 h Mpc<SUP>-1</SUP>. An updated version of our publicly available
HMCODE can be found at https://github.com/alexander-mead/hmcode.Fissel, L. M.: Balloon-Borne Submillimeter Polarimetry of the Vela C Molecular Cloud: Systematic Dependence of Polarization Fraction on Column Density and Local Polarization-Angle Dispersion
http://adsabs.harvard.edu/abs/2016ApJ...824..134F
We present results for Vela C obtained during the 2012 flight of the
Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry. We
mapped polarized intensity across almost the entire extent of this giant
molecular cloud, in bands centered at 250, 350, and 500 μm. In this
initial paper, we show our 500 μm data smoothed to a resolution of
2.‧5 (approximately 0.5 pc). We show that the mean level of the
fractional polarization p and most of its spatial variations can be
accounted for using an empirical three-parameter power-law fit, p
\propto {{\boldsymbol{N}}}<SUP>-0.45</SUP>
{{\boldsymbol{S}}}<SUP>-0.60</SUP>, where N is the hydrogen column
density and S is the polarization-angle dispersion on 0.5 pc scales. The
decrease of p with increasing S is expected because changes in the
magnetic field direction within the cloud volume sampled by each
measurement will lead to cancellation of polarization signals. The
decrease of p with increasing N might be caused by the same effect, if
magnetic field disorder increases for high column density sightlines.
Alternatively, the intrinsic polarization efficiency of the dust grain
population might be lower for material along higher density sightlines.
We find no significant correlation between N and S. Comparison of
observed submillimeter polarization maps with synthetic polarization
maps derived from numerical simulations provides a promising method for
testing star formation theories. Realistic simulations should allow for
the possibility of variable intrinsic polarization efficiency. The
measured levels of correlation among p, N, and S provide points of
comparison between observations and simulations.Alvarez, M. A.: The Kinetic Sunyaev-Zel’dovich Effect from Reionization: Simulated Full-sky Maps at Arcminute Resolution
http://adsabs.harvard.edu/abs/2016ApJ...824..118A
The kinetic Sunyaev-Zel’dovich (kSZ) effect results from
Thomson scattering by coherent flows in the reionized intergalactic
medium. We present new results based on ray-tracing an 8 Gpc/h
realization of reionization with resolution elements 2 Mpc/h (subtending
˜ 1‧ at z = 6) on a side to create a full-sky kSZ map. The
realization includes, self-consistently, the effects of reionization on
scales corresponding to multipoles 10≲ {\ell }≲ 5000. We
separate the kSZ map into Doppler ({\boldsymbol{v}}),
Ostriker-Vishniac (δ {\boldsymbol{v}}), patchy
(x{\boldsymbol{v}}), and third-order (xδ {\boldsymbol{v}})
components, and compute explicitly all the auto- and cross-correlations
(e.g., < {\boldsymbol{vv}}> , < δ
{\boldsymbol{v}}x{\boldsymbol{v}}> , etc.) that contribute to the
total power. We find a complex and nonmonotonic dependence on the
duration of reionization at {\ell }˜ 300 and evidence for a
non-negligible (10%-30%) contribution from connected four-point
correlations, < x{\boldsymbol{v}}x{\boldsymbol{v}}{>
}<SUB>c</SUB>, usually neglected in analytical models. We also
investigate the cross-correlation of linear matter and large-scale kSZ
temperature fluctuations, focusing on (1) cross-power spectra with
biased tracers of the matter density and (2) cold spots from infall onto
large, rare H ii regions centered on peaks in the matter distribution at
redshifts z\gt 10 that are a generic non-Gaussian feature of patchy
reionization. Finally, we show that the reionization history can be
reconstructed at 5σ-10σ significance by correlating
full-sky 21 cm maps stacked in bins with {{Δ }}ν = 10 {{MHz}}
with existing cosmic microwave background (CMB) temperature maps at
{\ell }\lt 500, raising the prospects for probing reionization by
correlating CMB and LSS measurements. The resulting kSZ maps have been
made publicly available at <A href="http://www.cita.utoronto.ca/~malvarez/research/ksz-data/">www.cita.utoronto.ca/~malvarez/research/ksz-data/</A>.Gandilo, N. N.: Submillimeter Polarization Spectrum in the Vela C Molecular Cloud
http://adsabs.harvard.edu/abs/2016ApJ...824...84G
Polarization maps of the Vela C molecular cloud were obtained at 250,
350, and 500 μm during the 2012 flight of the balloon-borne telescope
BLASTPol. These measurements are used in conjunction with 850 μm data
from Planck to study the submillimeter spectrum of the polarization
fraction for this cloud. The spectrum is relatively flat and does not
exhibit a pronounced minimum at λ ˜ 350 μm as suggested
by previous measurements of other molecular clouds. The shape of the
spectrum does not depend strongly on the radiative environment of the
dust, as quantified by the column density or the dust temperature
obtained from Herschel data. The polarization ratios observed in Vela C
are consistent with a model of a porous clumpy molecular cloud being
uniformly heated by the interstellar radiation field.Deaton, M. B.: Erratum: “Black Hole-Neutron Star Mergers with a Hot Nuclear Equation of State: Outflow and Neutrino-cooled Disk for a Low-mass, High-Spin Case” (2013, ApJ, 776, 47)
http://adsabs.harvard.edu/abs/2016ApJ...824...62D
Not AvailableHoang, T.: Spinning Dust Emission from Ultra-small Silicates: Emissivity and Polarization Spectrum
http://adsabs.harvard.edu/abs/2016ApJ...824...18H
Anomalous microwave emission (AME) is an important Galactic foreground
of cosmic microwave background radiation. It is believed that AME arises
from rotational emission by spinning polycyclic aromatic hydrocarbons in
the interstellar medium (ISM). In this paper, we suppose that a new
population of ultra-small silicate grains perhaps exists in the ISM, and
quantify the rotational emissivity from these tiny particles and its
polarization spectrum. We find that spinning silicate nanoparticles can
produce strong rotational emission when the tiny grains follow a
log-normal size distribution. The polarization fraction of spinning dust
emission from tiny silicates increases with decreasing dipole moment per
atom (β) and can reach P˜ 20 % for β ˜ 0.1 {{D}}
at a grain temperature of 60 K. We identify a parameter space (β
,{Y}<SUB>{{Si</SUB>}}), with {Y}<SUB>{{Si</SUB>}} being the fraction of
Si abundance in nanoparticles, in which its rotational emission can
adequately reproduce both the observed AME and the polarization of the
AME, without violating the observational constraints of ultraviolet
extinction and polarization of starlight. Our results reveal that
rotational emission from spinning silicate may be an important source of
AME.Bolmont, E.: Habitability of planets on eccentric orbits: Limits of the mean flux approximation
http://adsabs.harvard.edu/abs/2016A%26A...591A.106B
Unlike the Earth, which has a small orbital eccentricity, some
exoplanets discovered in the insolation habitable zone (HZ) have high
orbital eccentricities (e.g., up to an eccentricity of ~0.97 for HD
20782 b). This raises the question of whether these planets have surface
conditions favorable to liquid water. In order to assess the
habitability of an eccentric planet, the mean flux approximation is
often used. It states that a planet on an eccentric orbit is called
habitable if it receives on average a flux compatible with the presence
of surface liquid water. However, because the planets experience
important insolation variations over one orbit and even spend some time
outside the HZ for high eccentricities, the question of their
habitability might not be as straightforward. We performed a set of
simulations using the global climate model LMDZ to explore the limits of
the mean flux approximation when varying the luminosity of the host star
and the eccentricity of the planet. We computed the climate of tidally
locked ocean covered planets with orbital eccentricity from 0 to 0.9
receiving a mean flux equal to Earth's. These planets are found around
stars of luminosity ranging from 1 L<SUB>⊙</SUB> to
10<SUP>-4</SUP>L<SUB>⊙</SUB>. We use a definition of habitability
based on the presence of surface liquid water, and find that most of the
planets considered can sustain surface liquid water on the dayside with
an ice cap on the nightside. However, for high eccentricity and high
luminosity, planets cannot sustain surface liquid water during the whole
orbital period. They completely freeze at apoastron and when approaching
periastron an ocean appears around the substellar point. We conclude
that the higher the eccentricity and the higher the luminosity of the
star, the less reliable the mean flux approximation.Rivera-Ingraham, A.: Galactic cold cores. VII. Filament formation and evolution: Methods and observational constraints
http://adsabs.harvard.edu/abs/2016A%26A...591A..90R
Context. The association of filaments with protostellar objects has made
these structures a priority target in star formation studies. However,
little is known about the link between filament properties and their
local environment. <BR /> Aims: The datasets from the Herschel Galactic
Cold cores key programme allow for a statistical study of filaments with
a wide range of intrinsic and environmental characteristics.
Characterisation of this sample can therefore be used to identify key
physical parameters and quantify the role of the environment in the
formation of supercritical filaments. These results are necessary to
constrain theoretical models of filament formation and evolution. <BR />
Methods: Filaments were extracted from fields at distance D< 500 pc
with the getfilaments algorithm and characterised according to their
column density profiles and intrinsic properties. Each profile was
fitted with a beam-convolved Plummer-like function, and the filament
structure was quantified based on the relative contributions from the
filament "core", represented by a Gaussian, and "wing" component,
dominated by the power-law behaviour of the Plummer-like function. These
filament parameters were examined for populations associated with
different background levels. <BR /> Results: Filaments increase their
core (M<SUB>line,core</SUB>) and wing (M<SUB>line,wing</SUB>)
contributions while increasing their total linear mass density
(M<SUB>line,tot</SUB>). Both components appear to be linked to the local
environment, with filaments in higher backgrounds having systematically
more massive M<SUB>line,core</SUB> and M<SUB>line,wing</SUB>. This
dependence on the environment supports an accretion-based model of
filament evolution in the local neighbourhood (D ≤ 500 pc).
Structures located in the highest backgrounds develop the highest
central A<SUB>V</SUB>, M<SUB>line,core</SUB>, and M<SUB>line,wing</SUB>
as M<SUB>line,tot</SUB> increases with time, favoured by the local
availability of material and the enhanced gravitational potential. Our
results indicate that filaments acquiring a significantly massive
central region with M<SUB>line,core</SUB>≳M<SUB>crit</SUB>/2 may
become supercritical and form stars. This translates into a need for
filaments to become at least moderately self-gravitating to undergo
localised star formation or become star-forming filaments.
Herschel is an ESA space observatory with science instruments provided
by European-led Principal Investigator consortia and with important
participation from NASA.Vacca, V.: Using rotation measure grids to detect cosmological magnetic fields: A Bayesian approach
http://adsabs.harvard.edu/abs/2016A%26A...591A..13V
Determining magnetic field properties in different environments of the
cosmic large-scale structure as well as their evolution over redshift is
a fundamental step toward uncovering the origin of cosmic magnetic
fields. Radio observations permit the study of extragalactic magnetic
fields via measurements of the Faraday depth of extragalactic radio
sources. Our aim is to investigate how much different extragalactic
environments contribute to the Faraday depth variance of these sources.
We develop a Bayesian algorithm to distinguish statistically Faraday
depth variance contributions intrinsic to the source from those due to
the medium between the source and the observer. In our algorithm the
Galactic foreground and measurement noise are taken into account as the
uncertainty correlations of the Galactic model. Additionally, our
algorithm allows for the investigation of possible redshift evolution of
the extragalactic contribution. This work presents the derivation of the
algorithm and tests performed on mock observations. Because cosmic
magnetism is one of the key science projects of the new generation of
radio interferometers, we have predicted the performance of our
algorithm on mock data collected with these instruments. According to
our tests, high-quality catalogs of a few thousands of sources should
already enable us to investigate magnetic fields in the cosmic
structure.Connor, L.: FRB repetition and non-Poissonian statistics
http://adsabs.harvard.edu/abs/2016MNRAS.458L..89C
We discuss some of the claims that have been made regarding the
statistics of fast radio bursts (FRBs). In an earlier Letter, we
conjectured that flicker noise associated with FRB repetition could show
up in non-cataclysmic neutron star emission models, like supergiant
pulses. We show how the current limits of repetition would be
significantly weakened if their repeat rate really were non-Poissonian
and had a pink or red spectrum. Repetition and its statistics have
implications for observing strategy, generally favouring shallow
wide-field surveys, since in the non-repeating scenario survey depth is
unimportant. We also discuss the statistics of the apparent latitudinal
dependence of FRBs, and offer a simple method for calculating the
significance of this effect. We provide a generalized Bayesian framework
for addressing this problem, which allows for direct model comparison.
It is shown how the evidence for a steep latitudinal gradient of the FRB
rate is less strong than initially suggested and simple explanations
like increased scattering and sky temperature in the plane are
sufficient to decrease the low-latitude burst rate, given current data.
The reported dearth of bursts near the plane is further complicated if
FRBs have non-Poissonian repetition, since in that case the event rate
inferred from observation depends on observing strategy.Connor, L.: Non-cosmological FRBs from young supernova remnant pulsars
http://adsabs.harvard.edu/abs/2016MNRAS.458L..19C
We propose a new extra but non-cosmological explanation for fast radio
bursts (FRBs) based on very young pulsars in supernova remnants. Within
a few hundred years of a core-collapse supernova, the ejecta is confined
within ˜1 pc, providing a high enough column density of free
electrons for the observed 375-1600 pc cm<SUP>-3</SUP> of dispersion
measure (DM). By extrapolating a Crab-like pulsar to its infancy in an
environment like that of SN 1987A, we hypothesize such an object could
emit supergiant pulses sporadically which would be bright enough to be
seen at a few hundred megaparsecs. We hypothesize that such supergiant
pulses would preferentially occur early in the pulsar's life when the
free electron density is still high, which is why we do not see large
numbers of moderate DM FRBs (≲300 pc cm<SUP>-3</SUP>). In this
scenario, Faraday rotation at the source gives rotation measures (RMs)
much larger than the expected cosmological contribution. If the emission
were pulsar-like, then the polarization vector could swing over the
duration of the burst, which is not expected from non-rotating objects.
In this model, the scattering, large DM, and commensurate RM all come
from one place which is not the case for the cosmological
interpretation. The model also provides testable predictions of the flux
distribution and repeat rate of FRBs, and could be furthermore verified
by spatial coincidence with optical supernovae of the past several
decades and cross-correlation with nearby galaxy maps.Russell, H. R.: ALMA observations of cold molecular gas filaments trailing rising radio bubbles in PKS 0745-191
http://adsabs.harvard.edu/abs/2016MNRAS.458.3134R
We present ALMA observations of the CO(1-0) and CO(3-2) line emission
tracing filaments of cold molecular gas in the central galaxy of the
cluster PKS 0745-191. The total molecular gas mass of 4.6±
0.3× 10<SUP>9</SUP> M_{⊙}, assuming a Galactic X<SUB>CO</SUB>
factor, is divided roughly equally between three filaments each
extending radially 3-5 kpc from the galaxy centre. The emission peak is
located in the SE filament ˜ 1 arcsec (2 kpc) from the nucleus.
The velocities of the molecular clouds in the filaments are low, lying
within ± 100 { km s^{-1}} of the galaxy's systemic velocity.
Their full width at half-maximum (FWHM) are less than 150 { km s^{-1},}
which is significantly below the stellar velocity dispersion. Although
the molecular mass of each filament is comparable to a rich spiral
galaxy, such low velocities show that the filaments are transient and
the clouds would disperse on < 10<SUP>7</SUP> yr time-scales unless
supported, likely by the indirect effect of magnetic fields. The
velocity structure is inconsistent with a merger origin or gravitational
free-fall of cooling gas in this massive central galaxy. If the
molecular clouds originated in gas cooling even a few kpc from their
current locations their velocities would exceed those observed. Instead,
the projection of the N and SE filaments underneath X-ray cavities
suggests they formed in the updraft behind bubbles buoyantly rising
through the cluster atmosphere. Direct uplift of the dense gas by the
radio bubbles appears to require an implausibly high coupling
efficiency. The filaments are coincident with low temperature X-ray gas,
bright optical line emission and dust lanes indicating that the
molecular gas could have formed from lifted warmer gas that cooled in
situ.Crichton, D.: Evidence for the thermal Sunyaev-Zel'dovich effect associated with quasar feedback
http://adsabs.harvard.edu/abs/2016MNRAS.458.1478C
Using a radio-quiet subsample of the Sloan Digital Sky Survey
spectroscopic quasar catalogue, spanning redshifts 0.5-3.5, we derive
the mean millimetre and far-infrared quasar spectral energy
distributions (SEDs) via a stacking analysis of Atacama Cosmology
Telescope and Herschel-Spectral and Photometric Imaging REceiver data.
We constrain the form of the far-infrared emission and find
3σ-4σ evidence for the thermal Sunyaev-Zel'dovich (SZ)
effect, characteristic of a hot ionized gas component with thermal
energy (6.2 ± 1.7) × 10<SUP>60</SUP> erg. This amount of
thermal energy is greater than expected assuming only hot gas in virial
equilibrium with the dark matter haloes of (1-5) × 10<SUP>12</SUP>
h<SUP>-1</SUP> M<SUB>⊙</SUB> that these systems are expected to
occupy, though the highest quasar mass estimates found in the literature
could explain a large fraction of this energy. Our measurements are
consistent with quasars depositing up to (14.5 ± 3.3)τ_8^{-1}
per cent of their radiative energy into their circumgalactic environment
if their typical period of quasar activity is τ<SUB>8</SUB> ×
10<SUP>8</SUP> yr. For high quasar host masses, ˜10<SUP>13</SUP>
h<SUP>-1</SUP> M<SUB>⊙</SUB>, this percentage will be reduced.
Furthermore, the uncertainty on this percentage is only statistical and
additional systematic uncertainties enter at the 40 per cent level. The
SEDs are dust dominated in all bands and we consider various models for
dust emission. While sufficiently complex dust models can obviate the SZ
effect, the SZ interpretation remains favoured at the 3σ-4σ
level for most models.Liu, S.: Pulsar lensing geometry
http://adsabs.harvard.edu/abs/2016MNRAS.458.1289L
We test the inclined sheet pulsar scintillation model (Pen & Levin)
against archival very long baseline interferometry (VLBI) data on PSR
0834+06 and show that its scintillation properties can be precisely
reproduced by a model in which refraction occurs on two distinct lens
planes. These data strongly favour a model in which grazing-incidence
refraction instead of diffraction off turbulent structures is the
primary source of pulsar scattering. This model can reproduce the
parameters of the observed diffractive scintillation with an accuracy at
the percent level. Comparison with new VLBI proper motion results in a
direct measure of the ionized interstellar medium (ISM) screen
transverse velocity. The results are consistent with ISM velocities
local to the PSR 0834+06 sight-line (through the Galaxy). The simple 1-D
structure of the lenses opens up the possibility of using interstellar
lenses as precision probes for pulsar lens mapping, precision transverse
motions in the ISM, and new opportunities for removing scattering to
improve pulsar timing. We describe the parameters and observables of
this double screen system. While relative screen distances can in
principle be accurately determined, a global conformal distance
degeneracy exists that allows a rescaling of the absolute distance
scale. For PSR B0834+06, we present VLBI astrometry results that provide
(for the first time) a direct measurement of the distance of the pulsar.
For most of the recycled millisecond pulsars that are the targets of
precision timing observations, the targets where independent distance
measurements are not available. The degeneracy presented in the lens
modelling could be broken if the pulsar resides in a binary system.Hopkins, P. F.: Stellar and quasar feedback in concert: effects on AGN accretion, obscuration, and outflows
http://adsabs.harvard.edu/abs/2016MNRAS.458..816H
We study the interaction of feedback from active galactic nuclei (AGN)
and a multiphase interstellar medium (ISM), in simulations including
explicit stellar feedback, multiphase cooling, accretion-disc winds, and
Compton heating. We examine radii ˜0.1-100 pc around a black hole
(BH), where the accretion rate on to the BH is determined and where
AGN-powered winds and radiation couple to the ISM. We conclude: (1) the
BH accretion rate is determined by exchange of angular momentum between
gas and stars in gravitational instabilities. This produces accretion
rates ˜0.03-1 M<SUB>⊙</SUB> yr<SUP>-1</SUP>, sufficient to
power luminous AGN. (2) The gas disc in the galactic nucleus undergoes
an initial burst of star formation followed by several million years
where stellar feedback suppresses the star formation rate (SFR). (3) AGN
winds injected at small radii with momentum fluxes
˜L<SUB>AGN</SUB>/c couple efficiently to the ISM and have dramatic
effects on ISM properties within ˜100 pc. AGN winds suppress the
nuclear SFR by factors ˜10-30 and BH accretion rate by factors
˜3-30. They increase the outflow rate from the nucleus by factors
˜10, consistent with observational evidence for galaxy-scale
AGN-driven outflows. (4) With AGN feedback, the predicted column density
distribution to the BH is consistent with observations. Absent AGN
feedback, the BH is isotropically obscured and there are not enough
optically thin sightlines to explain type-I AGN. A `torus-like' geometry
arises self-consistently as AGN feedback evacuates gas in polar regions.Jacquet, E.: Northwest Africa 5958: A weakly altered CM-related ungrouped chondrite, not a CI3
http://adsabs.harvard.edu/abs/2016M%26PS...51..851J
Northwest Africa (NWA) 5958 is a carbonaceous chondrite found in Morocco
in 2009. Preliminary chemical and isotopic data leading to its initial
classification as C3.0 ungrouped have prompted us to conduct a
multitechnique study of this meteorite and present a general description
here. The petrography and chemistry of NWA 5958 is most similar to a CM
chondrite, with a low degree of aqueous alteration, apparently under
oxidizing conditions, and evidence of a second, limited alteration
episode manifested by alteration fronts. The oxygen isotopic
composition, with ∆'<SUP>17</SUP>O = -4.3‰, is more
<SUP>16</SUP>O-rich than all CM chondrites, indicating, along with other
compositional arguments, a separate parent body of origin. We suggest
that NWA 5958 be reclassified as an ungrouped carbonaceous chondrite
related to the CM group.Jontof-Hutter, D.: Eccentricity Inferences in Multi-planet systems with Transit Timing: Degeneracies and Apsidal Alignment
http://adsabs.harvard.edu/abs/2016DDA....4720204J
Hundreds of multi-transiting systems discovered by the Kepler mission
show Transit Timing Variations (TTV). In cases where the TTVs are
uniquely attributable to transiting planets, the TTVs enable precise
measurements of planetary masses and orbital parameters. Of particular
interest are the constraints on eccentricity vectors that can be
inferred in systems of low-mass exoplanets.The TTVs in these systems are
dominated by a signal caused by near-resonant mean motions. This causes
the well-known near-degeneracy between planetary masses and orbital
eccentricities. In addition, it causes a degeneracy between the
eccentricities of interacting planet pairs.For many systems, the
magnitude of individual eccentricities are weakly constrained, yet the
data typically provide a tight constraint on the posterior joint
distribution for the eccentricity vector components. This permits tight
constraints on the relative eccentricity and degree of alignment of
interacting planets.For a sample of two and three-planet systems with
TTVs, we highlight the effects of these correlations. While the most
eccentric orbital solutions for these systems show apsidal alignment,
this is often due to the degeneracy that causes correlated constraints
on the eccentricity vector components. We compare the likelihood of
apsidal alignment for two choices of eccentricity prior: a wide prior
using a Rayleigh distribution of scale length 0.1 and a narrower prior
with scale length 0.02. In all cases the narrower prior decreased the
fraction of samples that exhibited apsidal alignment. However, apsidal
alignment persisted in the majority of cases with a narrower
eccentricity prior. For a sample of our TTV solutions, we ran
simulations of these systems over secular timescales, and decomposed
their eccentricity eigenmodes over time, confirming that in most cases,
the eccentricities were dominated by parallel eigenmodes which favor
apsidal alignment.Obertas, A.: The Stability of Tightly-packed and Evenly-spaced Planetary Systems
http://adsabs.harvard.edu/abs/2016DDA....4720203O
Many of the multi-planet systems discovered to date have been notable
for their compactness, with neighbouring planets closer together than
any in the Solar System. Interestingly, planet hosting stars have a wide
range of ages, suggesting that such compact systems can survive for
extended periods of time. We have used numerical simulations to
investigate how quickly systems go unstable in relation to
thecompactness of a system. So far, we have focused on hypothetical
systems of Earth-mass planets on evenly spaced orbits (in mutual Hill
Radii). In general, the further apart the planets are initially, the
longer it takes for a pair of planets to undergo a close encounter. We
recover the results of previous studies, showing a linear trend in the
initial planet spacing between 3-8 Hill Radii and the log of close
encounter time. However, investigating thousands of simulations reveals
further, more detailed structure superimposed on this relationship. We
discuss the impact of this structure and the implications on the
stability of compact multi-planet systems.Van Laerhoven, C. L.: Effect of Unseen Planets on Secular Interactions
http://adsabs.harvard.edu/abs/2016DDA....4710501V
A great number of multi-planet extra-solar systems are now known thanks
to both transit and radial velocity surveys. The long-term eccentricity
and inclination behavior of many of these systems is readily described
by classical second-order secular theory in which the eccentricity and
inclination of each planet is a sum of contributions from several
eigenmodes. The underlying structure of the eigenmodes, that is, how
much each planet is affected by a given eigenmode, depends on only the
masses and semi-major axes of the planets, and the mass of the star.
When discerning the dynamics of a system it is usually assumed that the
known planets are the only planets in the system, or at least that any
other planets are distant enough to not strongly affect the known
planets. However, the secular structure might change significantly if
there are one or more additional, unseen planets in the system. I will
discuss how the secular structure of several observed multi-planet
systems changes when an additional planet is added to the system, and
how that change in the secular structure depends on the mass and
distance of the additional planet.Henriksson, K.: Initial data for high-compactness black hole-neutron star binaries
http://adsabs.harvard.edu/abs/2016CQGra..33j5009H
For highly compact neutron stars, constructing numerical initial data
for black hole-neutron star binary evolutions is very difficult.
We describe improvements to an earlier method that enable it to handle
these more challenging cases. These improvements were found by invoking
a general relaxation principle that may be helpful in improving
robustness in other initial data solvers. We examine the case of a 6:1
mass ratio system in inspiral close to merger, where the star is
governed by a polytropic {{Γ }}=2, an SLy, or an LS220 equation of
state (EOS). In particular, we are able to obtain a solution with a
realistic LS220 EOS for a star with compactness 0.26 and mass 1.98 M
<SUB>⊙</SUB>, which is representative of the highest reliably
determined neutron star masses. For the SLy EOS, we can obtain solutions
with a comparable compactness of 0.25, while for a family of polytropic
equations of state, we obtain solutions with compactness up to 0.21, the
largest compactness that is stable in this family. These compactness
values are significantly higher than any previously published results.Hezaveh, Y. D.: Detection of Lensing Substructure Using ALMA Observations of the Dusty Galaxy SDP.81
http://adsabs.harvard.edu/abs/2016ApJ...823...37H
We study the abundance of substructure in the matter density near
galaxies using ALMA Science Verification observations of the strong
lensing system SDP.81. We present a method to measure the abundance of
subhalos around galaxies using interferometric observations of
gravitational lenses. Using simulated ALMA observations we explore the
effects of various systematics, including antenna phase errors and
source priors, and show how such errors may be measured or marginalized.
We apply our formalism to ALMA observations of SDP.81. We find evidence
for the presence of a M = 10<SUP>8.96±0.12</SUP> M
<SUB>⊙</SUB> subhalo near one of the images, with a significance of
6.9σ in a joint fit to data from bands 6 and 7; the effect of the
subhalo is also detected in both bands individually. We also derive
constraints on the abundance of dark matter (DM) subhalos down to M
˜ 2 × 10<SUP>7</SUP> M <SUB>⊙</SUB>, pushing down to the
mass regime of the smallest detected satellites in the Local Group,
where there are significant discrepancies between the observed
population of luminous galaxies and predicted DM subhalos. We find hints
of additional substructure, warranting further study using the full
SDP.81 data set (including, for example, the spectroscopic imaging of
the lensed carbon monoxide emission). We compare the results of this
search to the predictions of ΛCDM halos, and find that given
current uncertainties in the host halo properties of SDP.81, our
measurements of substructure are consistent with theoretical
expectations. Observations of larger samples of gravitational lenses
with ALMA should be able to improve the constraints on the abundance of
galactic substructure.Zhu, H.-M.: Probing Neutrino Hierarchy and Chirality via Wakes
http://adsabs.harvard.edu/abs/2016PhRvL.116n1301Z
The relic neutrinos are expected to acquire a bulk relative velocity
with respect to the dark matter at low redshifts, and neutrino wakes are
expected to develop downstream of the dark matter halos. We propose a
method of measuring the neutrino mass based on this mechanism. This
neutrino wake will cause a dipole distortion of the galaxy-galaxy
lensing pattern. This effect could be detected by combining upcoming
lensing surveys with a low redshift galaxy survey or a 21 cm intensity
mapping survey, which can map the neutrino flow field. The data obtained
with LSST and Euclid should enable us to make a positive detection if
the three neutrino masses are quasidegenerate with each neutrino mass of
˜0.1 eV , and a future high precision 21 cm lensing survey would
allow the normal hierarchy and inverted hierarchy cases to be
distinguished, and even the right-handed Dirac neutrinos may be
detectable.Abbott, B. P.: GW150914: The Advanced LIGO Detectors in the Era of First Discoveries
http://adsabs.harvard.edu/abs/2016PhRvL.116m1103A
Following a major upgrade, the two advanced detectors of the Laser
Interferometer Gravitational-wave Observatory (LIGO) held their first
observation run between September 2015 and January 2016. With a strain
sensitivity of 10<SUP>-23</SUP>/√{Hz } at 100 Hz, the product of
observable volume and measurement time exceeded that of all previous
runs within the first 16 days of coincident observation. On September
14, 2015, the Advanced LIGO detectors observed a transient
gravitational-wave signal determined to be the coalescence of two black
holes [B. P. Abbott et al., Phys. Rev. Lett. 116, 061102 (2016)],
launching the era of gravitational-wave astronomy. The event, GW150914,
was observed with a combined signal-to-noise ratio of 24 in coincidence
by the two detectors. Here, we present the main features of the
detectors that enabled this observation. At full sensitivity, the
Advanced LIGO detectors are designed to deliver another factor of 3
improvement in the signal-to-noise ratio for binary black hole systems
similar in mass to GW150914.Abbott, B. P.: GW150914: Implications for the Stochastic Gravitational-Wave Background from Binary Black Holes
http://adsabs.harvard.edu/abs/2016PhRvL.116m1102A
The LIGO detection of the gravitational wave transient GW150914, from
the inspiral and merger of two black holes with masses ≳30
M<SUB>⊙</SUB>, suggests a population of binary black holes with
relatively high mass. This observation implies that the stochastic
gravitational-wave background from binary black holes, created from the
incoherent superposition of all the merging binaries in the Universe,
could be higher than previously expected. Using the properties of
GW150914, we estimate the energy density of such a background from
binary black holes. In the most sensitive part of the Advanced LIGO and
Advanced Virgo band for stochastic backgrounds (near 25 Hz), we predict
Ω<SUB>GW</SUB>(f =25 Hz )=1.
1<SUB>-0.9</SUB><SUP>+2.7</SUP>×10<SUP>-9</SUP> with 90%
confidence. This prediction is robustly demonstrated for a variety of
formation scenarios with different parameters. The differences between
models are small compared to the statistical uncertainty arising from
the currently poorly constrained local coalescence rate. We conclude
that this background is potentially measurable by the Advanced LIGO and
Advanced Virgo detectors operating at their projected final sensitivity.Schaan, E.: Evidence for the kinematic Sunyaev-Zel'dovich effect with the Atacama Cosmology Telescope and velocity reconstruction from the Baryon Oscillation Spectroscopic Survey
http://adsabs.harvard.edu/abs/2016PhRvD..93h2002S
We use microwave temperature maps from two seasons of data from the
Atacama Cosmology Telescope at 146 GHz, together with the "Constant
Mass" CMASS galaxy sample from the Baryon Oscillation Spectroscopic
Survey to measure the kinematic Sunyaev-Zel'dovich (kSZ) effect over the
redshift range z =0.4 - 0.7 . We use galaxy positions and the continuity
equation to obtain a reconstruction of the line-of-sight velocity field.
We stack the microwave temperature at the location of each halo,
weighted by the corresponding reconstructed velocity. We vary the size
of the aperture photometry filter used, thus probing the free electron
profile of these halos from within the virial radius out to three virial
radii, on the scales relevant for investigating the missing baryons
problem. The resulting best fit kSZ model is preferred over the no-kSZ
hypothesis at 3.3 and 2.9 σ for two independent velocity
reconstruction methods, using 25,537 galaxies over 660 square degrees.
The data suggest that the baryon profile is shallower than the dark
matter in the inner regions of the halos probed here, potentially due to
energy injection from active galactic nucleus or supernovae. Thus, by
constraining the gas profile on a wide range of scales, this technique
will be useful for understanding the role of feedback in galaxy groups
and clusters. The effect of foregrounds that are uncorrelated with the
galaxy velocities is expected to be well below our signal, and residual
thermal Sunyaev-Zel'dovich contamination is controlled by masking the
most massive clusters. Finally, we discuss the systematics involved in
converting our measurement of the kSZ amplitude into the mean free
electron fraction of the halos in our sample.Bolmont, E.: Habitability of planets on eccentric orbits: limits of the mean flux approximation
http://adsabs.harvard.edu/abs/2016EGUGA..18..382B
A few of the planets found in the insolation habitable zone (region in
which a planet with an atmosphere can sustain surface liquid water,
Kasting et al. 1993) are on eccentric orbits, such as GJ 667Cc
(eccentricity of < 0.3, Anglada-Escude et al. 2012) or HD 16175 b
(eccentricity of 0.6, Peek et al. 2009). This raises the question of the
potential habitability of planets that only spend a fraction of their
orbit in the habitable zone. Usually for a planet of semi-major axis a
and eccentricity e, the averaged flux over one orbit received by the
planet is considered. This averaged flux corresponds to the flux
received by a planet on a circular orbit of radius r = a(1
-e2)1/4. If this orbital distance is within the habitable zone,
the planet is said "habitable". However, for a hot star, for which the
habitable zone is far from the star, the climate can be degraded when
the planet is temporarily outside the habitable zone. We investigate
here the limits of validity of the mean flux approximation used to
assess the potential habitability of eccentric planets. For this study,
we consider ocean planets in synchronized rotation and planets with a
rotation period of 24 hr. We investigate the influence of the type of
host star and the eccentricity of the orbit on the climate of a planet.
We do so by scaling the duration of its orbital period and its apastron
and periastron distance to ensure that it receives in average the same
incoming flux as Earth's. We performed sets of 3D simulations using the
Global Climate Model LMDz (Wordsworth et al. 2011, Forget et al. 2013,
Leconte et al. 2013). The atmosphere is composed of N2, CO2 and H2O
(gas, liquid, solid) in Earth-like proportions. First, we do not take
into account the spectral difference between a low luminosity star and a
Sun-like star. Second, the dependence of the albedo of ice and snow on
the spectra of the host star is taken into account. This influences the
positive ice-albedo feedback and can lead to a different climatic
evolution. We show that the higher the eccentricity and the higher the
luminosity of the star, the less reliable the mean flux approximation.Isoyama, S.: Self-force and fluid resonances
http://adsabs.harvard.edu/abs/2016CQGra..33h5002I
The gravitational self-force acting on a particle orbiting a massive
central body has thus far been computed for vacuum spacetimes involving
a black hole. In this work we continue an ongoing effort to study the
self-force in nonvacuum situations. We replace the black hole by a
material body consisting of a perfect fluid, and determine the impact of
the fluid's dynamics on the self-force and resulting orbital evolution.
We show that as the particle inspirals toward the fluid body, its
gravitational perturbations trigger a number of quasinormal modes of the
fluid-gravity system, which produce resonant features in the
conservative and dissipative components of the self-force. As a
proof-of-principle, we demonstrate this phenomenon in a simplified
framework in which gravity is mediated by a scalar potential satisfying
a wave equation in Minkowski spacetime.Broderick, A. E.: Modeling Seven Years of Event Horizon Telescope Observations with Radiatively Inefficient Accretion Flow Models
http://adsabs.harvard.edu/abs/2016ApJ...820..137B
An initial three-station version of the Event Horizon Telescope, a
millimeter-wavelength very-long baseline interferometer, has observed
Sagittarius A* (Sgr A*) repeatedly from 2007 to 2013, resulting in the
measurement of a variety of interferometric quantities. Of particular
importance is that there is now a large set of closure phases measured
over a number of independent observing epochs. We analyze these
observations within the context of a realization of semi-analytic
radiatively inefficient disk models, implicated by the low luminosity of
Sgr A*. We find a broad consistency among the various observing epochs
and between different interferometric data types, with the latter
providing significant support for this class of model of Sgr A*. The new
data significantly tighten existing constraints on the spin magnitude
and its orientation within this model context, finding a spin magnitude
of a={0.10}<SUB>-0.10-0.10</SUB><SUP>+0.30+0.56</SUP>, an inclination
with respect to the line of sight of θ ={60^\circ
}<SUB>-{8</SUB><SUP>^\circ </SUP>-{13}<SUP>^\circ
</SUP>}<SUP>+{5</SUP><SUP>^\circ </SUP>+{10}<SUP>^\circ </SUP>}, and a
position angle of ξ ={156^\circ }<SUB>-{17</SUB><SUP>^\circ
</SUP>-{27}<SUP>^\circ </SUP>}<SUP>+{10</SUP><SUP>^\circ
</SUP>+{14}<SUP>^\circ </SUP>} east of north. These are in good
agreement with previous analyses. Notably, the previous 180°
degeneracy in the position angle has now been conclusively broken by the
inclusion of the closure-phase measurements. A reflection degeneracy in
the inclination remains, permitting two localizations of the spin vector
orientation, one of which is in agreement with the orbital angular
momentum of the infrared gas cloud G2 and the clockwise disk of young
stars. This may support a relationship between Sgr A*'s accretion flow
and these larger-scale features.Fish, V. L.: Persistent Asymmetric Structure of Sagittarius A* on Event Horizon Scales
http://adsabs.harvard.edu/abs/2016ApJ...820...90F
The Galactic Center black hole Sagittarius A* (Sgr A*) is a prime
observing target for the Event Horizon Telescope (EHT), which can
resolve the 1.3 mm emission from this source on angular scales
comparable to that of the general relativistic shadow. Previous EHT
observations have used visibility amplitudes to infer the morphology of
the millimeter-wavelength emission. Potentially much richer source
information is contained in the phases. We report on 1.3 mm phase
information on Sgr A* obtained with the EHT on a total of 13 observing
nights over four years. Closure phases, which are the sum of visibility
phases along a closed triangle of interferometer baselines, are used
because they are robust against phase corruptions introduced by
instrumentation and the rapidly variable atmosphere. The median closure
phase on a triangle including telescopes in California, Hawaii, and
Arizona is nonzero. This result conclusively demonstrates that the
millimeter emission is asymmetric on scales of a few Schwarzschild radii
and can be used to break 180° rotational ambiguities inherent from
amplitude data alone. The stability of the sign of the closure phase
over most observing nights indicates persistent asymmetry in the image
of Sgr A* that is not obscured by refraction due to interstellar
electrons along the line of sight.Bertincourt, B.: Comparison of absolute gain photometric calibration between Planck/HFI and Herschel/SPIRE at 545 and 857 GHz
http://adsabs.harvard.edu/abs/2016A%26A...588A.107B
We compare the absolute gain photometric calibration of the Planck/HFI
and Herschel/SPIRE instruments on diffuse emission. The absolute
calibration of HFI and SPIRE each relies on planet flux measurements and
comparison with theoretical far-infrared emission models of planetary
atmospheres. We measure the photometric cross calibration between the
instruments at two overlapping bands, 545 GHz/500 μm and 857 GHz/350
μm. The SPIRE maps used have been processed in the Herschel
Interactive Processing Environment (Version 12) and the HFI data are
from the 2015 Public Data Release 2. For our study we used 15 large
fields observed with SPIRE, which cover a total of about 120
deg<SUP>2</SUP>. We have selected these fields carefully to provide high
signal-to-noise ratio, avoid residual systematics in the SPIRE maps, and
span a wide range of surface brightness. The HFI maps are
bandpass-corrected to match the emission observed by the SPIRE
bandpasses. The SPIRE maps are convolved to match the HFI beam and put
on a common pixel grid. We measure the cross-calibration relative gain
between the instruments using two methods in each field, pixel-to-pixel
correlation and angular power spectrum measurements. The SPIRE/HFI
relative gains are 1.047 (±0.0069) and 1.003 (±0.0080) at
545 and 857 GHz, respectively, indicating very good agreement between
the instruments. These relative gains deviate from unity by much less
than the uncertainty of the absolute extended emission calibration,
which is about 6.4% and 9.5% for HFI and SPIRE, respectively, but the
deviations are comparable to the values 1.4% and 5.5% for HFI and SPIRE
if the uncertainty from models of the common calibrator can be
discounted. Of the 5.5% uncertainty for SPIRE, 4% arises from the
uncertainty of the effective beam solid angle, which impacts the adopted
SPIRE point source to extended source unit conversion factor,
highlighting that as a focus for refinement.Baldauf, T.: Peak exclusion, stochasticity and convergence of perturbative bias expansions in 1+1 gravity
http://adsabs.harvard.edu/abs/2016MNRAS.456.3985B
The Lagrangian peaks of a 1D cosmological random field representing dark
matter are used as a proxy for a catalogue of biased tracers in order to
investigate the small-scale exclusion in the two-halo term. The
two-point correlation function of peaks of a given height is numerically
estimated and analytical approximations that are valid inside the
exclusion zone are derived. The resulting power spectrum of these
tracers is investigated and shows clear deviations from Poisson noise at
low frequencies. On large scales, the convergence of a perturbative bias
expansion is discussed. Finally, we go beyond Gaussian statistics for
the initial conditions and investigate the subsequent evolution of the
two-point clustering of peaks through their Zel'dovich ballistic
displacement, to clarify how exclusion effects mix up with
scale-dependences induced by non-linear gravitational evolution. While
the expected large-scale separation limit is recovered, significant
deviations are found in the exclusion zone that tends in particular to
be reduced at later times. Even though these findings apply to the
clustering of 1D tracers, they provide useful insights into halo
exclusion and its impact on the two-halo term.Green, D.: Constraints on primordial magnetic fields from inflation
http://adsabs.harvard.edu/abs/2016JCAP...03..010G
We present generic bounds on magnetic fields produced from cosmic
inflation. By investigating field bounds on the vector potential, we
constrain both the quantum mechanical production of magnetic fields and
their classical growth in a model independent way. For classical growth,
we show that only if the reheating temperature is as low as
T<SUB>reh</SUB> lesssim 10<SUP>2</SUP> MeV can magnetic fields of
10<SUP>-15</SUP> G be produced on Mpc scales in the present
universe. For purely quantum mechanical scenarios, even stronger
constraints are derived. Our bounds on classical and quantum mechanical
scenarios apply to generic theories of inflationary magnetogenesis with
a two-derivative time kinetic term for the vector potential. In both
cases, the magnetic field strength is limited by the gravitational
back-reaction of the electric fields that are produced simultaneously.
As an example of quantum mechanical scenarios, we construct vector field
theories whose time diffeomorphisms are spontaneously broken, and
explore magnetic field generation in theories with a variable speed of
light. Transitions of quantum vector field fluctuations into classical
fluctuations are also analyzed in the examples.Yang, H.: Testing Gravity Using Pulsar Scintillation Measurements
http://adsabs.harvard.edu/abs/2016APS..APRX15003Y
We propose to use pulsar scintillation measurements to test predictions
of alternative theories of gravity. Comparing to single-path pulsar
timing measurements, the scintillation measurements can achieve a factor
of 10<SUP>4</SUP> ~10<SUP>5</SUP> improvement in timing accuracy, due to
the effect of multi-path interference. The self-noise from pulsar also
does not affect the interference pattern, where the data acquisition
timescale is 10<SUP>3</SUP> seconds instead of years. Therefore it has
unique advantages in measuring gravitational effect or other mechanisms
(at mHz and above frequencies) on light propagation. We illustrate its
application in constraining scalar gravitational-wave background and
measuring gravitational-wave speed, in which cases the sensitivities are
greatly improved with respect to previous limits. We expect much broader
applications in testing gravity with existing and future pulsar
scintillation observations.Vincent, T.: Computing Binary Black Hole Initial Data with Discontinuous Galerkin Methods
http://adsabs.harvard.edu/abs/2016APS..APRU15006V
Discontinuous Galerkin (DG) finite element methods have been used to
solve hyperbolic PDEs in relativistic simulations and offer advantages
over traditional discretization methods. Comparatively little attention
has been given towards using the DG method to solve the elliptic PDEs
arising from the Einstein initial data equations. We describe how the DG
method can be used to create a parallel, adaptive solver for initial
data. We discuss the use of our dG code to compute puncture initial data
for binary black holes.Mark, Z.: Model for Quasinormal Mode Excitation by a Particle Plunging into a Black Hole
http://adsabs.harvard.edu/abs/2016APS..APRR15009M
It is known that the late time gravitational waveform produced by a
particle plunging into a Kerr black hole is well described by a sum of
quasinormal modes. However it is not yet understood how the early part
of the waveform gives way to the quasinormal mode description, which
diverges at early times, nor how the inhomogenous part of the waveform
contributes. Motivated by, we offer a model for quasinormal mode
excitation by a particle plunging into a Schwarzschild black hole. To
develop our model we study approximations to the Regge-Wheeler equation
that allow for a closed-form expression for the frequency-domain Green's
function, which we use to isolate the component of the waveform that
should be identified with quasinormal ringing. Our description of
quasinormal ringing does not diverge at early times and reveals that
quasinormal ringing should be understood in analogy with a damped
harmonic oscillator experiencing a transient driving source.Zimmerman, A.: Measuring the redshift factor in binary black hole simulations
http://adsabs.harvard.edu/abs/2016APS..APRK15003Z
The redshift factor z is an invariant quantity of fundamental interest
in Post-Newtonian and self-force descriptions of circular binaries. It
allows for interconnections between each theory, and plays a central
role in the Laws of Binary Black Hole Mechanics, which link local
quantities to asymptotic measures of energy and angular momentum in
these systems. Through these laws, the redshift factor is conjectured to
have a close relation to the surface gravity of the event horizons of
black holes in circular orbits. We have implemented a novel method for
extracting the redshift factor on apparent horizons in numerical
simulations of quasicircular binary inspirals. Our results confirm the
conjectured relationship between z and the surface gravity of the holes.
This redshift factor allows us to test PN and self-force predictions for
z in spacetimes where the binary is only approximately circular, and
allows for an array of new comparisons between analytic approximations
and numerical simulations. I will present our new method, our initial
results in using z to verify the Laws of Binary Black Holes Mechanics,
and discuss future directions for this work.Jontof-Hutter, D.: Secure Mass Measurements from Transit Timing: 10 Kepler Exoplanets between 3 and 8 M⊕ with Diverse Densities and Incident Fluxes
http://adsabs.harvard.edu/abs/2016ApJ...820...39J
We infer dynamical masses in eight multiplanet systems using transit
times measured from Kepler's complete data set, including short-cadence
data where available. Of the 18 dynamical masses that we infer, 10 pass
multiple tests for robustness. These are in systems Kepler-26 (KOI-250),
Kepler-29 (KOI-738), Kepler-60 (KOI-2086), Kepler-105 (KOI-115), and
Kepler-307 (KOI-1576). Kepler-105 c has a radius of 1.3
R<SUB>⊕</SUB> and a density consistent with an Earth-like
composition. Strong transit timing variation (TTV) signals were detected
from additional planets, but their inferred masses were sensitive to
outliers or consistent solutions could not be found with independently
measured transit times, including planets orbiting Kepler-49 (KOI-248),
Kepler-57 (KOI-1270), Kepler-105 (KOI-115), and Kepler-177 (KOI-523).
Nonetheless, strong upper limits on the mass of Kepler-177 c imply an
extremely low density of ˜0.1 g cm<SUP>-3</SUP>. In most
cases, individual orbital eccentricities were poorly constrained owing
to degeneracies in TTV inversion. For five planet pairs in our sample,
strong secular interactions imply a moderate to high likelihood of
apsidal alignment over a wide range of possible eccentricities. We also
find solutions for the three planets known to orbit Kepler-60 in a
Laplace-like resonance chain. However, nonlibrating solutions also match
the transit timing data. For six systems, we calculate more precise
stellar parameters than previously known, enabling useful constraints on
planetary densities where we have secure mass measurements. Placing
these exoplanets on the mass-radius diagram, we find that a wide
range of densities is observed among sub-Neptune-mass planets and that
the range in observed densities is anticorrelated with incident flux.Wang, X.: Statistical Decoupling of a Lagrangian Fluid Parcel in Newtonian Cosmology
http://adsabs.harvard.edu/abs/2016ApJ...820...30W
The Lagrangian dynamics of a single fluid element within a
self-gravitational matter field is intrinsically non-local due to the
presence of the tidal force. This complicates the theoretical
investigation of the nonlinear evolution of various cosmic objects,
e.g., dark matter halos, in the context of Lagrangian fluid dynamics,
since fluid parcels with given initial density and shape may evolve
differently depending on their environments. In this paper, we provide a
statistical solution that could decouple this environmental dependence.
After deriving the evolution equation for the probability distribution
of the matter field, our method produces a set of closed ordinary
differential equations whose solution is uniquely determined by the
initial condition of the fluid element. Mathematically, it corresponds
to the projected characteristic curve of the transport equation of the
density-weighted probability density function (ρPDF). Consequently
it is guaranteed that the one-point ρPDF would be preserved by
evolving these local, yet nonlinear, curves with the same set of initial
data as the real system. Physically, these trajectories describe the
mean evolution averaged over all environments by substituting the tidal
tensor with its conditional average. For Gaussian distributed dynamical
variables, this mean tidal tensor is simply proportional to the velocity
shear tensor, and the dynamical system would recover the prediction of
the Zel’dovich approximation (ZA) with the further assumption of
the linearized continuity equation. For a weakly non-Gaussian field, the
averaged tidal tensor could be expanded perturbatively as a function of
all relevant dynamical variables whose coefficients are determined by
the statistics of the field.Campbell, J. L.: Contraction Signatures toward Dense Cores in the Perseus Molecular Cloud
http://adsabs.harvard.edu/abs/2016ApJ...819..143C
We report the results of an HCO<SUP>+</SUP> (3-2) and
N<SUB>2</SUB>D<SUP>+</SUP> (3-2) molecular line survey performed
toward 91 dense cores in the Perseus molecular cloud using the James
Clerk Maxwell Telescope, to identify the fraction of starless and
protostellar cores with systematic radial motions. We quantify the
HCO<SUP>+</SUP> asymmetry using a dimensionless asymmetry parameter
δ<SUB>v</SUB>, and identify 20 cores with significant blue or red
line asymmetries in optically thick emission indicative of collapsing or
expanding motions, respectively. We separately fit the HCO<SUP>+</SUP>
profiles with an analytic collapse model and determine contraction
(expansion) speeds toward 22 cores. Comparing the δ<SUB>v</SUB>
and collapse model results, we find that δ<SUB>v</SUB> is a good
tracer of core contraction if the optically thin emission is aligned
with the model-derived systemic velocity. The contraction speeds range
from subsonic (0.03 km s<SUP>-1</SUP>) to supersonic (0.4 km
s<SUP>-1</SUP>), where the supersonic contraction speeds may trace
global rather than local core contraction. Most cores have contraction
speeds significantly less than their free-fall speeds. Only 7 of 28
starless cores have spectra well-fit by the collapse model, which more
than doubles (15 of 28) for protostellar cores. Starless cores with
masses greater than the Jeans mass (M/M<SUB>J</SUB> > 1) are somewhat
more likely to show contraction motions. We find no trend of optically
thin non-thermal line width with M/M<SUB>J</SUB>, suggesting that any
undetected contraction motions are small and subsonic. Most starless
cores in Perseus are either not in a state of collapse or expansion, or
are in a very early stage of collapse.Abbott, B. P.: Observation of Gravitational Waves from a Binary Black Hole Merger
http://adsabs.harvard.edu/abs/2016PhRvL.116f1102A
On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser
Interferometer Gravitational-Wave Observatory simultaneously observed a
transient gravitational-wave signal. The signal sweeps upwards in
frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0
×10<SUP>-21</SUP>. It matches the waveform predicted by general
relativity for the inspiral and merger of a pair of black holes and the
ringdown of the resulting single black hole. The signal was observed
with a matched-filter signal-to-noise ratio of 24 and a false alarm rate
estimated to be less than 1 event per 203 000 years, equivalent to a
significance greater than 5.1 σ . The source lies at a luminosity
distance of 41 0<SUB>-180</SUB><SUP>+160</SUP> Mpc corresponding to a
redshift z =0.0 9<SUB>-0.04</SUB><SUP>+0.03</SUP> . In the source frame,
the initial black hole masses are 3
6<SUB>-4</SUB><SUP>+5</SUP>M<SUB>⊙</SUB> and 2
9<SUB>-4</SUB><SUP>+4</SUP>M<SUB>⊙</SUB> , and the final black hole
mass is 6 2<SUB>-4</SUB><SUP>+4</SUP>M<SUB>⊙</SUB> , with 3.
0<SUB>-0.5</SUB><SUP>+0.5</SUP>M<SUB>⊙</SUB> c<SUP>2</SUP> radiated
in gravitational waves. All uncertainties define 90% credible intervals.
These observations demonstrate the existence of binary stellar-mass
black hole systems. This is the first direct detection of gravitational
waves and the first observation of a binary black hole merger.Foucart, F.: Low mass binary neutron star mergers: Gravitational waves and neutrino emission
http://adsabs.harvard.edu/abs/2016PhRvD..93d4019F
Neutron star mergers are among the most promising sources of
gravitational waves for advanced ground-based detectors. These mergers
are also expected to power bright electromagnetic signals, in the form
of short gamma-ray bursts, infrared/optical transients powered by
r-process nucleosynthesis in neutron-rich material ejected by the
merger, and radio emission from the interaction of that ejecta with the
interstellar medium. Simulations of these mergers with fully general
relativistic codes are critical to understand the merger and postmerger
gravitational wave signals and their neutrinos and electromagnetic
counterparts. In this paper, we employ the Spectral Einstein Code to
simulate the merger of low mass neutron star binaries (two 1.2
M<SUB>⊙</SUB> neutron stars) for a set of three
nuclear-theory-based, finite temperature equations of state. We show
that the frequency peaks of the postmerger gravitational wave signal are
in good agreement with predictions obtained from recent simulations
using a simpler treatment of gravity. We find, however, that only the
fundamental mode of the remnant is excited for long periods of time:
emission at the secondary peaks is damped on a millisecond time scale in
the simulated binaries. For such low mass systems, the remnant is a
massive neutron star which, depending on the equation of state, is
either permanently stable or long lived (i.e. rapid uniform rotation is
sufficient to prevent its collapse). We observe strong excitations of l
=2 , m =2 modes, both in the massive neutron star and in the form of
hot, shocked tidal arms in the surrounding accretion torus. We estimate
the neutrino emission of the remnant using a neutrino leakage scheme
and, in one case, compare these results with a gray two-moment neutrino
transport scheme. We confirm the complex geometry of the neutrino
emission, also observed in previous simulations with neutrino leakage,
and show explicitly the presence of important differences in the
neutrino luminosity, disk composition, and outflow properties between
the neutrino leakage and transport schemes.Huang, Z.: Observational effects of a running Planck mass
http://adsabs.harvard.edu/abs/2016PhRvD..93d3538H
We consider observational effects of a running effective Planck mass in
the scalar-tensor gravity theory. At the background level, an increasing
effective Planck mass allows a larger Hubble constant H<SUB>0</SUB>,
which is more compatible with the local direct measurements. At the
perturbative level, for cosmic microwave background (CMB) anisotropies,
an increasing effective Planck mass (i) suppresses the unlensed CMB
power at ℓ≲30 via the integrated Sachs-Wolfe effect and (ii)
enhances CMB lensing power. Both effects slightly relax the tension
between the current CMB data from the Planck satellite and the standard
Λ CDM model predictions. However, these impacts on the CMB
secondary anisotropies are subdominant, and the overall constraints are
driven by the background measurements. Combining CMB data from the
Planck satellite and an H<SUB>0</SUB> prior from Riess et al., we find a
˜2 σ hint of a positive running of the effective Planck
mass. However, the hint goes away when we add other low-redshift
observational data including type Ia supernovae, baryon acoustic
oscillations, and an estimation of the age of the Universe using the old
stars.Meerburg, P. D.: Joint resonant CMB power spectrum and bispectrum estimation
http://adsabs.harvard.edu/abs/2016PhRvD..93d3536M
We develop the tools necessary to assess the statistical significance of
resonant features in the CMB correlation functions, combining power
spectrum and bispectrum measurements. This significance is typically
addressed by running a large number of simulations to derive the
probability density function (PDF) of the feature-amplitude in the
Gaussian case. Although these simulations are tractable for the power
spectrum, for the bispectrum they require significant computational
resources. We show that, by assuming that the PDF is given by a
multivariate Gaussian where the covariance is determined by the Fisher
matrix of the sine and cosine terms, we can efficiently produce spectra
that are statistically close to those derived from full simulations. By
drawing a large number of spectra from this PDF, both for the power
spectrum and the bispectrum, we can quickly determine the statistical
significance of candidate signatures in the CMB, considering both single
frequency and multifrequency estimators. We show that for resonance
models, cosmology and foreground parameters have little influence on the
estimated amplitude, which allows us to simplify the analysis
considerably. A more precise likelihood treatment can then be applied to
candidate signatures only. We also discuss a modal expansion approach
for the power spectrum, aimed at quickly scanning through large families
of oscillating models.Aasi, J.: Search of the Orion spur for continuous gravitational waves using a loosely coherent algorithm on data from LIGO interferometers
http://adsabs.harvard.edu/abs/2016PhRvD..93d2006A
We report results of a wideband search for periodic gravitational waves
from isolated neutron stars within the Orion spur towards both the inner
and outer regions of our Galaxy. As gravitational waves interact very
weakly with matter, the search is unimpeded by dust and concentrations
of stars. One search disk (A) is 6.87° in diameter and centered on 2
0<SUP>h</SUP>1 0<SUP>m</SUP>54.7 1<SUP>s</SUP>+3 3 ° 3
3<SUP>'</SUP>25.2 9<SUP>''</SUP> , and the other (B) is 7.45° in
diameter and centered on 8<SUP>h</SUP>3 5<SUP>m</SUP>20.6
1<SUP>s</SUP>-4 6 ° 4 9<SUP>'</SUP>25.15 1<SUP>''</SUP>. We explored
the frequency range of 50-1500 Hz and frequency derivative from 0 to -5
×10<SUP>-9</SUP> Hz /s . A multistage, loosely coherent search
program allowed probing more deeply than before in these two regions,
while increasing coherence length with every stage. Rigorous follow-up
parameters have winnowed the initial coincidence set to only 70
candidates, to be examined manually. None of those 70 candidates proved
to be consistent with an isolated gravitational-wave emitter, and 95%
confidence level upper limits were placed on continuous-wave strain
amplitudes. Near 169 Hz we achieve our lowest 95% C.L. upper limit on
the worst-case linearly polarized strain amplitude h<SUB>0</SUB> of 6.3
×10<SUP>-25</SUP>, while at the high end of our frequency range we
achieve a worst-case upper limit of 3.4 ×10<SUP>-24</SUP> for all
polarizations and sky locations.Abbott, B. P.: All-sky search for long-duration gravitational wave transients with initial LIGO
http://adsabs.harvard.edu/abs/2016PhRvD..93d2005A
We present the results of a search for long-duration gravitational wave
transients in two sets of data collected by the LIGO Hanford and LIGO
Livingston detectors between November 5, 2005 and September 30, 2007,
and July 7, 2009 and October 20, 2010, with a total observational time
of 283.0 days and 132.9 days, respectively. The search targets
gravitational wave transients of duration 10-500 s in a frequency band
of 40-1000 Hz, with minimal assumptions about the signal waveform,
polarization, source direction, or time of occurrence. All candidate
triggers were consistent with the expected background; as a result we
set 90% confidence upper limits on the rate of long-duration
gravitational wave transients for different types of gravitational wave
signals. For signals from black hole accretion disk instabilities, we
set upper limits on the source rate density between 3.4 ×1
0<SUP>-5</SUP> and 9.4 ×1 0<SUP>-4</SUP> Mpc<SUP>-3</SUP>
yr<SUP>-1</SUP> at 90% confidence. These are the first results from an
all-sky search for unmodeled long-duration transient gravitational
waves.Abbott, B. P.: Astrophysical Implications of the Binary Black-hole Merger GW150914
http://adsabs.harvard.edu/abs/2016ApJ...818L..22A
The discovery of the gravitational-wave (GW) source GW150914 with the
Advanced LIGO detectors provides the first observational evidence for
the existence of binary black hole (BH) systems that inspiral and merge
within the age of the universe. Such BH mergers have been predicted in
two main types of formation models, involving isolated binaries in
galactic fields or dynamical interactions in young and old dense stellar
environments. The measured masses robustly demonstrate that relatively
“heavy” BHs (≳ 25 {M}<SUB>⊙ </SUB>) can form in
nature. This discovery implies relatively weak massive-star winds and
thus the formation of GW150914 in an environment with a metallicity
lower than about 1/2 of the solar value. The rate of binary-BH (BBH)
mergers inferred from the observation of GW150914 is consistent with the
higher end of rate predictions (≳ 1 Gpc<SUP>-3</SUP>
yr<SUP>-1</SUP>) from both types of formation models. The low
measured redshift (z≃ 0.1) of GW150914 and the low inferred
metallicity of the stellar progenitor imply either BBH formation in a
low-mass galaxy in the local universe and a prompt merger, or formation
at high redshift with a time delay between formation and merger of
several Gyr. This discovery motivates further studies of binary-BH
formation astrophysics. It also has implications for future detections
and studies by Advanced LIGO and Advanced Virgo, and GW detectors in
space.Correia, C.: Principal Component Analysis Studies of Turbulence in Optically Thick Gas
http://adsabs.harvard.edu/abs/2016ApJ...818..118C
In this work we investigate the sensitivity of principal component
analysis (PCA) to the velocity power spectrum in high-opacity regimes of
the interstellar medium (ISM). For our analysis we use synthetic
position-position-velocity (PPV) cubes of fractional
Brownian motion and magnetohydrodynamics (MHD) simulations,
post-processed to include radiative transfer effects from CO. We find
that PCA analysis is very different from the tools based on the
traditional power spectrum of PPV data cubes. Our major finding is that
PCA is also sensitive to the phase information of PPV cubes and this
allows PCA to detect the changes of the underlying velocity and density
spectra at high opacities, where the spectral analysis of the maps
provides the universal -3 spectrum in accordance with the
predictions of the Lazarian & Pogosyan theory. This makes PCA a
potentially valuable tool for studies of turbulence at high opacities,
provided that proper gauging of the PCA index is made. However, we found
the latter to not be easy, as the PCA results change in an irregular way
for data with high sonic Mach numbers. This is in contrast to synthetic
Brownian noise data used for velocity and density fields that show
monotonic PCA behavior. We attribute this difference to the PCA's
sensitivity to Fourier phase information.Csengeri, T.: ATLASGAL-selected massive clumps in the inner Galaxy. II. Characterisation of different evolutionary stages and their SiO emission
http://adsabs.harvard.edu/abs/2016A%26A...586A.149C
Context. The processes leading to the birth of high-mass stars are
poorly understood. The key first step to reveal their formation
processes is characterising the clumps and cores from which they form.
<BR /> Aims: We define a representative sample of massive clumps in
different evolutionary stages selected from the APEX Telescope Large
Area Survey of the Galaxy (ATLASGAL), from which we aim to establish a
census of molecular tracers of their evolution. As a first step, we
study the shock tracer, SiO, mainly associated with shocks from jets
probing accretion processes. In low-mass young stellar objects (YSOs),
outflow and jet activity decreases with time during the star formation
processes. Recently, a similar scenario was suggested for massive clumps
based on SiO observations. Here we analyse observations of the SiO (2-1)
and (5-4) lines in a statistically significant sample to constrain the
change of SiO abundance and the excitation conditions as a function of
evolutionary stage of massive star-forming clumps. <BR /> Methods: We
performed an unbiased spectral line survey covering the 3-mm atmospheric
window between 84-117 GHz with the IRAM 30 m telescope of a sample of
430 sources of the ATLASGAL survey, covering various evolutionary stages
of massive clumps. A smaller sample of 128 clumps has been observed in
the SiO (5-4) transition with the APEX telescope to complement the (2-1)
line and probe the excitation conditions of the emitting gas. We derived
detection rates to assess the star formation activity of the sample, and
we estimated the column density and abundance using both an LTE
approximation and non-LTE calculations for a smaller subsample, where
both transitions have been observed. <BR /> Results: We characterise the
physical properties of the selected sources, which greatly supersedes
the largest samples studied so far, and show that they are
representative of different evolutionary stages. We report a high
detection rate of >75% of the SiO (2-1) line and a >90% detection
rate from the dedicated follow-ups in the (5-4) transition. Up to 25% of
the infrared-quiet clumps exhibit high-velocity line wings, suggesting
that molecular tracers are more efficient tools to determine the level
of star formation activity than infrared colour criteria. We also find
infrared-quiet clumps that exhibit only a low-velocity component (FWHM ~
5-6 km s<SUP>-1</SUP>) SiO emission in the (2-1) line. In the current
picture, where this is attributed to low-velocity shocks from
cloud-cloud collisions, this can be used to pinpoint the youngest, thus,
likely prestellar massive structures. Using the optically thin
isotopologue (<SUP>29</SUP>SiO), we estimate that the (2-1) line is
optically thin towards most of the sample. Furthermore, based on the
line ratio of the (5-4) to the (2-1) line, our study reveals a trend of
changing excitation conditions that lead to brighter emission in the
(5-4) line towards more evolved sources. Our models show that a proper
treatment of non-LTE effects and beam dilution is necessary to constrain
trends in the SiO column density and abundance. <BR /> Conclusions: We
conclude that the SiO (2-1) line with broad line profiles and high
detection rates is a powerful probe of star formation activity in the
deeply embedded phase of the evolution of massive clumps. The ubiquitous
detection of SiO in all evolutionary stages suggests a continuous star
formation process in massive clumps. Our analysis delivers a more robust
estimate of SiO column density and abundance than previous studies and
questions the decrease of jet activity in massive clumps as a function
of age. The observed increase of excitation conditions towards the more
evolved clumps suggests a higher pressure in the shocked gas towards
more evolved or more massive clumps in our sample.
Full Tables 4, 6, 7 are only available at the CDS via anonymous ftp to
<A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A149">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A149</A>Planck Collaboration: Planck intermediate results. XXXVIII. E- and B-modes of dust polarization from the magnetized filamentary structure of the interstellar medium
http://adsabs.harvard.edu/abs/2016A%26A...586A.141P
The quest for a B-mode imprint from primordial gravity waves on the
polarization of the cosmic microwave background (CMB) requires the
characterization of foreground polarization from Galactic dust. We
present a statistical study of the filamentary structure of the 353 GHz
Planck Stokes maps at high Galactic latitude, relevant to the study of
dust emission as a polarized foreground to the CMB. We filter the
intensity and polarization maps to isolate filaments in the range of
angular scales where the power asymmetry between E-modes and B-modes is
observed. Using the Smoothed Hessian Major Axis Filament Finder (SMAFF),
we identify 259 filaments at high Galactic latitude, with lengths larger
or equal to 2° (corresponding to 3.5 pc in length for a typical
distance of 100 pc). Thesefilaments show a preferred orientation
parallel to the magnetic field projected onto the plane of the sky,
derived from their polarization angles. We present mean maps of the
filaments in Stokes I, Q, U, E, and B, computed by stacking individual
images rotated to align the orientations of the filaments. Combining the
stacked images and the histogram of relative orientations, we estimate
the mean polarization fraction of the filaments to be 11%. Furthermore,
we show that the correlation between the filaments and the magnetic
field orientations may account for the E and B asymmetry and the
C<SUB>ℓ</SUB><SUP>TE</SUP>/C<SUB>ℓ</SUB><SUP>EE</SUP> ratio,
reported in the power spectra analysis of the Planck353 GHz polarization
maps. Future models of the dust foreground for CMB polarization studies
will need to take into account the observed correlation between the dust
polarization and the structure of interstellar matter.Planck Collaboration: Planck intermediate results. XXXVII. Evidence of unbound gas from the kinetic Sunyaev-Zeldovich effect
http://adsabs.harvard.edu/abs/2016A%26A...586A.140P
By looking at the kinetic Sunyaev-Zeldovich effect (kSZ) in Planck
nominal mission data, we present a significant detection of baryons
participating in large-scale bulk flows around central galaxies (CGs) at
redshift z ≈ 0.1. We estimate the pairwise momentum of the kSZ
temperature fluctuations at the positions of the Central Galaxy
Catalogue (CGC) samples extracted from Sloan Digital Sky Survey
(SDSS-DR7) data. For the foreground-cleaned SEVEM, SMICA, NILC, and
COMMANDER maps, we find 1.8-2.5σ detections of the kSZ signal,
which are consistent with the kSZ evidence found in individualPlanck raw
frequency maps, although lower than found in the WMAP-9yr W-band
(3.3σ). We further reconstruct the peculiar velocity field from
the CG density field, and compute for the first time the
cross-correlation function between kSZ temperature fluctuations and
estimates of CG radial peculiar velocities. This correlation function
yields a 3.0-3.7σ detection of the peculiar motion of extended gas
on Mpc scales in flows correlated up to distances of 80-100
h<SUP>-1</SUP> Mpc. Both the pairwise momentum estimates and the kSZ
temperature-velocity field correlation find evidence for kSZ signatures
out to apertures of 8 arcmin and beyond, corresponding to a physical
radius of >1 Mpc, more than twice the mean virial radius of halos.
This is consistent with the predictions from hydrodynamical simulations
that most of the baryons are outside the virialized halos. We fit a
simple model, in which the temperature-velocity cross-correlation is
proportional to the signal seen in a semi-analytic model built upon
N-body simulations, and interpret the proportionality constant as an
effective optical depth to Thomson scattering. We find τ<SUB>T</SUB>
= (1.4 ± 0.5) × 10<SUP>-4</SUP>; the simplest
interpretation of this measurement is that much of the gas is in a
diffuse phase, which contributes little signal to X-ray or thermal
Sunyaev-Zeldovich observations.Planck Collaboration: Planck intermediate results. XXXVI. Optical identification and redshifts of Planck SZ sources with telescopes at the Canary Islands observatories
http://adsabs.harvard.edu/abs/2016A%26A...586A.139P
We present the results of approximately three years of observations of
Planck Sunyaev-Zeldovich (SZ) sources with telescopes at the Canary
Islands observatories as part of the general optical follow-up programme
undertaken by the Planck Collaboration. In total, 78 SZ sources are
discussed. Deep-imaging observations were obtained for most of these
sources; spectroscopic observations in either in long-slit or
multi-object modes were obtained for many. We effectively used 37.5
clear nights. We found optical counterparts for 73 of the 78 candidates.
This sample includes 53 spectroscopic redshift determinations, 20 of
them obtained with a multi-object spectroscopic mode. The sample
contains new redshifts for 27 Planck clusters that were not included in
the first Planck SZ source catalogue (PSZ1).Planck Collaboration: Planck intermediate results. XXXV. Probing the role of the magnetic field in the formation of structure in molecular clouds
http://adsabs.harvard.edu/abs/2016A%26A...586A.138P
Within ten nearby (d < 450 pc) Gould belt molecular clouds we
evaluate statistically the relative orientation between the magnetic
field projected on the plane of sky, inferred from the polarized thermal
emission of Galactic dust observed by Planck at 353 GHz, and the gas
column density structures, quantified by the gradient of the column
density, N<SUB>H</SUB>. The selected regions, covering several degrees
in size, are analysed at an effective angular resolution of 10' FWHM,
thus sampling physical scales from 0.4 to 40 pc in the nearest cloud.
The column densities in the selected regions range from
N<SUB>H</SUB>≈ 10<SUP>21</SUP> to10<SUP>23</SUP> cm<SUP>-2</SUP>, and
hence they correspond to the bulk of the molecular clouds. The relative
orientation is evaluated pixel by pixel and analysed in bins of column
density using the novel statistical tool called "histogram of relative
orientations". Throughout this study, we assume that the polarized
emission observed by Planck at 353 GHz is representative of the
projected morphology of the magnetic field in each region, i.e., we
assume a constant dust grain alignment efficiency, independent of the
local environment. Within most clouds we find that the relative
orientation changes progressively with increasing N<SUB>H</SUB>, from
mostly parallel or having no preferred orientation to mostly
perpendicular. In simulations of magnetohydrodynamic turbulence in
molecular clouds this trend in relative orientation is a signature of
Alfvénic or sub-Alfvénic turbulence, implying that the
magnetic field is significant for the gas dynamics at the scales probed
by Planck. We compare the deduced magnetic field strength with estimates
we obtain from other methods and discuss the implications of the Planck
observations for the general picture of molecular cloud formation and
evolution.Planck Collaboration: Planck intermediate results. XXXIV. The magnetic field structure in the Rosette Nebula
http://adsabs.harvard.edu/abs/2016A%26A...586A.137P
Planck has mapped the polarized dust emission over the whole sky, making
it possible to trace the Galactic magnetic field structure that pervades
the interstellar medium (ISM). We combine polarization data from Planck
with rotation measure (RM) observations towards a massive star-forming
region, the Rosette Nebula in the Monoceros molecular cloud, to study
its magnetic field structure and the impact of an expanding H ii region
on the morphology of the field. We derive an analytical solution for the
magnetic field, assumed to evolve from an initially uniform
configuration following the expansion of ionized gas and the formation
of a shell of swept-up ISM. From the RM data we estimate a mean value of
the line-of-sight component of the magnetic field of about 3 μG
(towards the observer) in the Rosette Nebula, for a uniform electron
density of about 12 cm<SUP>-3</SUP>. The dust shell that surrounds the
Rosette H ii region is clearly observed in the Planck intensity map at
353 GHz, with a polarization signal significantly different from that of
the local background when considered asa whole. The Planck observations
constrain the plane-of-the-sky orientation of the magnetic field in the
Rosette's parent molecular cloud to be mostly aligned with the
large-scale field along the Galactic plane. The Planck data are compared
with the analytical model, which predicts the mean polarization
properties of a spherical and uniform dust shell for a given orientation
of the field. This comparison leads to an upper limit of about 45°
on the angle between the line of sight and the magnetic field in the
Rosette complex, for an assumed intrinsic dust polarization fraction of
4%. This field direction can reproduce the RM values detected in the
ionized region if the magnetic field strength in the Monoceros molecular
cloud is in the range 6.5-9 μG. The present analytical model is able
to reproduce the RM distribution across the ionized nebula, as well as
the mean dust polarization properties of the swept-up shell, and can be
directly applied to other similar objects.Planck Collaboration: Planck intermediate results. XXXIII. Signature of the magnetic field geometry of interstellar filaments in dust polarization maps
http://adsabs.harvard.edu/abs/2016A%26A...586A.136P
Planck observations at 353 GHz provide the first fully sampled maps of
the polarized dust emission towards interstellar filaments and their
backgrounds (i.e., the emission observed in the surroundings of the
filaments). The data allow us to determine the intrinsic polarization
properties of the filaments and therefore to provide insight into the
structure of their magnetic field (B). We present the polarization maps
of three nearby (several parsecs long) star-forming filaments of
moderate column density (N<SUB>H</SUB> about 10<SUP>22</SUP>
cm<SUP>-2</SUP>): Musca, B211, and L1506. These three filaments are
detected above the background in dust total and polarized emission. We
use the spatial information to separate Stokes I, Q, and U of the
filaments from those of their backgrounds, an essential step in
measuring the intrinsic polarization fraction (p) and angle (ψ) of
each emission component. We find that the polarization angles in the
three filaments (ψ<SUB>fil</SUB>) are coherent along their lengths
and not the same as in their backgrounds (ψ<SUB>bg</SUB>). The
differences between ψ<SUB>fil</SUB> and ψ<SUB>bg</SUB> are
12° and 54° for Musca and L1506, respectively, and only 6°
in the case of B211. These differences forMusca and L1506 are larger
than the dispersions of ψ, both along the filaments and in their
backgrounds. The observed changes of ψ are direct evidence of
variations of the orientation of the plane of the sky (POS) projection
of the magnetic field. As in previous studies, we find a decrease of
several per cent in p with N<SUB>H</SUB> from the backgrounds to the
crest of the filaments. We show that the bulk of the drop in p within
the filaments cannot be explained by random fluctuations of the
orientation of the magnetic field because they are too small
(σ<SUB>ψ</SUB>< 10°). We recognize the degeneracy
between the dust alignment efficiency (by, e.g., radiative torques) and
the structure of the B-field in causing variations in p, but we argue
that the decrease in p from the backgrounds to the filaments results in
part from depolarization associated with the 3D structure of the
B-field: both its orientation in the POS and with respect to the POS. We
do not resolve the inner structure of the filaments, but at the smallest
scales accessible with Planck (~0.2 pc), the observed changes of ψ
and p hold information on the magnetic field structure within filaments.
They show that both the mean field and its fluctuations in the filaments
are different from those of their backgrounds, which points to a
coupling between the matter and the B-field in the filament formation
process.Planck Collaboration: Planck intermediate results. XXXII. The relative orientation between the magnetic field and structures traced by interstellar dust
http://adsabs.harvard.edu/abs/2016A%26A...586A.135P
The role of the magnetic field in the formation of the filamentary
structures observed in the interstellar medium (ISM) is a debated topic
owing to the paucity of relevant observations needed to test existing
models. The Planck all-sky maps of linearly polarized emission from dust
at 353 GHz provide the required combination of imaging and statistics to
study the correlation between the structures of the Galactic magnetic
field and of interstellar matter over the whole sky, both in the diffuse
ISM and in molecular clouds. The data reveal that structures, or ridges,
in the intensity map have counterparts in the Stokes Q and/or U maps. We
focus our study on structures at intermediate and high Galactic
latitudes, which cover two orders of magnitude in column density, from
10<SUP>20</SUP> to 10<SUP>22</SUP> cm<SUP>-2</SUP>. We measure the
magnetic field orientation on the plane ofthe sky from the polarization
data, and present an algorithm to estimate the orientation of the ridges
from the dust intensity map. We use analytical models to account for
projection effects. Comparing polarization angles on and off the
structures, we estimate the mean ratio between the strengths of the
turbulent and mean components of the magnetic field to be between 0.6
and 1.0, with a preferred value of 0.8. We find that the ridges are
usually aligned with the magnetic field measured on the structures. This
statistical trend becomes more striking for increasing polarization
fraction and decreasing column density. There is no alignment for the
highest column density ridges. We interpret the increase in alignment
with polarization fraction as a consequence of projection effects. We
present maps to show that the decrease in alignment for high column
density is not due to a loss of correlation between the distribution of
matter and the geometry of the magnetic field. In molecular complexes,
we also observe structures perpendicular to the magnetic field, which,
statistically, cannot be accounted for by projection effects. This first
statistical study of the relative orientation between the matter
structures and the magnetic field in the ISM points out that, at the
angular scales probed by Planck, the field geometry projected on the
plane of the sky is correlated with the distribution of matter. In the
diffuse ISM, the structures of matter are usually aligned with the
magnetic field, while perpendicular structures appear in molecular
clouds. We discuss our results in the context of models and MHD
simulations, which attempt to describe the respective roles of
turbulence, magnetic field, and self-gravity in the formation of
structures in the magnetized ISM.Planck Collaboration: Planck intermediate results. XXXI. Microwave survey of Galactic supernova remnants
http://adsabs.harvard.edu/abs/2016A%26A...586A.134P
The all-sky Planck survey in 9 frequency bands was used to search for
emission from all 274 known Galactic supernova remnants. Of these, 16
were detected in at least two Planck frequencies. The
radio-through-microwave spectral energy distributions were compiled to
determine the mechanism for microwave emission. In only one case, IC
443, is there high-frequency emission clearly from dust associated with
the supernova remnant. In all cases, the low-frequency emission is from
synchrotron radiation. As predicted for a population of relativistic
particles with energy distribution that extends continuously to high
energies, a single power law is evident for many sources, including the
Crab and PKS 1209-51/52. A decrease in flux density relative to the
extrapolation of radio emission is evident in several sources. Their
spectral energy distributions can be approximated as broken power laws,
S<SUB>ν</SUB> ∝ ν<SUP>-α</SUP>, with the spectral
index, α, increasing by 0.5-1 above a break frequency in the range
10-60 GHz. The break could be due to synchrotron losses.Planck Collaboration: Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes
http://adsabs.harvard.edu/abs/2016A%26A...586A.133P
The polarized thermal emission from diffuse Galactic dust is the main
foreground present in measurements of the polarization of the cosmic
microwave background (CMB) at frequencies above 100 GHz. In this paper
we exploit the uniqueness of the Planck HFI polarization data from 100
to 353 GHz to measure the polarized dust angular power spectra
C<SUB>ℓ</SUB><SUP>EE</SUP> and C<SUB>ℓ</SUB><SUP>BB</SUP> over
the multipole range 40 <ℓ< 600 well away from the Galactic
plane. These measurements will bring new insights into interstellar dust
physics and allow a precise determination of the level of contamination
for CMB polarization experiments. Despite the non-Gaussian and
anisotropic nature of Galactic dust, we show that general statistical
properties of the emission can be characterized accurately over large
fractions of the sky using angular power spectra. The polarization power
spectra of the dust are well described by power laws in multipole,
C<SUB>ℓ</SUB> ∝ ℓ<SUP>α</SUP>, with exponents
α<SUP>EE,BB</SUP> = -2.42 ± 0.02. The amplitudes of the
polarization power spectra vary with the average brightness in a way
similar to the intensity power spectra. The frequency dependence of the
dust polarization spectra is consistent with modified blackbody emission
with β<SUB>d</SUB> = 1.59 and T<SUB>d</SUB> = 19.6 K down to the
lowest Planck HFI frequencies. We find a systematic difference between
the amplitudes of the Galactic B- and E-modes,
C<SUB>ℓ</SUB><SUP>BB</SUP>/C<SUB>ℓ</SUB><SUP>EE</SUP> = 0.5. We
verify that these general properties are preserved towards high Galactic
latitudes with low dust column densities. We show that even in the
faintest dust-emitting regions there are no "clean" windows in the sky
where primordial CMB B-mode polarization measurements could be made
without subtraction of foreground emission. Finally, we investigate the
level of dust polarization in the specific field recently targeted by
the BICEP2 experiment. Extrapolation of the Planck 353 GHz data to 150
GHz gives a dust power 𝒟<SUB>ℓ</SUB><SUP>BB</SUP> ≡
ℓ(ℓ+1)C<SUB>ℓ</SUB><SUP>BB</SUP>/(2π) of 1.32 ×
10<SUP>-2</SUP> μK<SUB>CMB</SUB><SUP>2</SUP> over the multipole range
of the primordial recombination bump (40 <ℓ< 120); the
statistical uncertainty is ± 0.29 × 10<SUP>-2</SUP>
μK<SUB>CMB</SUB><SUP>2</SUP> and there is an additional uncertainty
(+0.28, -0.24) × 10<SUP>-2</SUP> μK<SUB>CMB</SUB><SUP>2</SUP>
from the extrapolation. This level is the same magnitude as reported by
BICEP2 over this ℓ range, which highlights the need for assessment
of the polarized dust signal even in the cleanest windows of the sky.Planck Collaboration: Planck intermediate results. XXIX. All-sky dust modelling with Planck, IRAS, and WISE observations
http://adsabs.harvard.edu/abs/2016A%26A...586A.132P
We present all-sky modelling of the high resolution Planck, IRAS, and
WISE infrared (IR) observations using the physical dust model presented
by Draine & Li in 2007 (DL, ApJ, 657, 810). We study the performance
and results of this model, and discuss implications for future dust
modelling. The present work extends the DL dust modelling carried out on
nearby galaxies using Herschel and Spitzer data to Galactic dust
emission. We employ the DL dust model to generate maps of the dust mass
surface density Σ<SUB>M<SUB>d</SUB></SUB>, the dust optical
extinction A<SUB>V</SUB>, and the starlight intensity heating the bulk
of the dust, parametrized by U<SUB>min</SUB>. The DL model reproduces
the observed spectral energy distribution (SED) satisfactorily over most
of the sky, with small deviations in the inner Galactic disk and in low
ecliptic latitude areas, presumably due to zodiacal light contamination.
In the Andromeda galaxy (M31), the present dust mass estimates agree
remarkably well (within 10%) with DL estimates based on independent
Spitzer and Herschel data. We compare the DL optical extinction
A<SUB>V</SUB> for the diffuse interstellar medium (ISM) with optical
estimates for approximately 2 × 10<SUP>5</SUP> quasi-stellar
objects (QSOs) observed inthe Sloan Digital Sky Survey (SDSS). The DL
A<SUB>V</SUB> estimates are larger than those determined towards QSOs by
a factor of about 2, which depends on U<SUB>min</SUB>. The DL fitting
parameter U<SUB>min</SUB>, effectively determined by the wavelength
where the SED peaks, appears to trace variations in the far-IR opacity
of the dust grains per unit A<SUB>V</SUB>, and not only in the starlight
intensity. These results show that some of the physical assumptions of
the DL model will need to be revised. To circumvent the model
deficiency, we propose an empirical renormalization of the DL
A<SUB>V</SUB> estimate, dependent of U<SUB>min</SUB>, which compensates
for the systematic differences found with QSO observations. This
renormalization, made to match the A<SUB>V</SUB> estimates towards QSOs,
also brings into agreement the DL A<SUB>V</SUB> estimates with those
derived for molecular clouds from the near-IR colours of stars in the 2
micron all sky survey (2MASS). The DL model and the QSOs data are also
used to compress the spectral information in the Planck and IRAS
observations for the diffuse ISM to a family of 20 SEDs normalized per
A<SUB>V</SUB>, parameterized by U<SUB>min</SUB>, which may be used to
test and empirically calibrate dust models. The family of SEDs and the
maps generated with the DL model are made public in the Planck Legacy
Archive.Meacher, D.: Second Einstein Telescope mock data and science challenge: Low frequency binary neutron star data analysis
http://adsabs.harvard.edu/abs/2016PhRvD..93b4018M
The Einstein Telescope is a conceived third-generation
gravitational-wave detector that is envisioned to be an order of
magnitude more sensitive than advanced LIGO, Virgo, and Kagra, which
would be able to detect gravitational-wave signals from the coalescence
of compact objects with waveforms starting as low as 1 Hz. With this
level of sensitivity, we expect to detect sources at cosmological
distances. In this paper we introduce an improved method for the
generation of mock data and analyze it with a new low-latency compact
binary search pipeline called gstlal. We present the results from this
analysis with a focus on low-frequency analysis of binary neutron stars.
Despite compact binary coalescence signals lasting hours in the Einstein
Telescope sensitivity band when starting at 5 Hz, we show that we are
able to discern various overlapping signals from one another. We also
determine the detection efficiency for each of the analysis runs
conducted and show a proof of concept method for estimating the number
signals as a function of redshift. Finally, we show that our ability to
recover the signal parameters has improved by an order of magnitude when
compared to the results of the first mock data and science challenge.
For binary neutron stars we are able to recover the total mass and chirp
mass to within 0.5% and 0.05%, respectively.Tiscareno, M. S.: Observing Planetary Rings and Small Satellites with the James Webb Space Telescope: Science Justification and Observation Requirements
http://adsabs.harvard.edu/abs/2016PASP..128a8008T
The James Webb Space Telescope (JWST) will provide unprecedented
opportunities to observe the rings and small satellites in our Solar
System, accomplishing three primary objectives: (1) discovering new
rings and moons, (2) unprecedented spectroscopy, and (3) time-domain
observations. We give details on these science objectives and describe
requirements that JWST must fulfill in order to accomplish the science
objectives.Baumann, D.: Phases of new physics in the CMB
http://adsabs.harvard.edu/abs/2016JCAP...01..007B
Fluctuations in the cosmic neutrino background are known to produce a
phase shift in the acoustic peaks of the cosmic microwave background. It
is through the sensitivity to this effect that the recent CMB data has
provided a robust detection of free-streaming neutrinos. In this paper,
we revisit the phase shift of the CMB anisotropy spectrum as a probe of
new physics. The phase shift is particularly interesting because its
physical origin is strongly constrained by the analytic properties of
the Green's function of the gravitational potential. For adiabatic
fluctuations, a phase shift requires modes that propagate faster than
the speed of fluctuations in the photon-baryon plasma. This possibility
is realized by free-streaming relativistic particles, such as neutrinos
or other forms of dark radiation. Alternatively, a phase shift can arise
from isocurvature fluctuations. We present simple models to illustrate
each of these effects. We then provide observational constraints from
the Planck temperature and polarization data on additional forms of
radiation. We also forecast the capabilities of future CMB Stage IV
experiments. Whenever possible, we give analytic interpretations of our
results.Sullivan, C.: The Sensitivity of Core-collapse Supernovae to Nuclear Electron Capture
http://adsabs.harvard.edu/abs/2016ApJ...816...44S
A weak-rate library aimed at investigating the sensitivity of
astrophysical environments to variations of electron-capture rates on
medium-heavy nuclei has been developed. With this library, the
sensitivity of the core-collapse and early post-bounce phases of
core-collapse supernovae to nuclear electron capture is examined. The
rates are adjusted by factors consistent with uncertainties indicated by
comparing theoretical rates to those deduced from charge-exchange and
β-decay measurements. To ensure a model-independent assessment,
sensitivity studies across a comprehensive set of progenitors and
equations of state are performed. We find a +16/-4% range in the
mass of the inner core at shock formation and a ±20% range of
peak {ν }<SUB>e</SUB> luminosity during the deleptonization burst.
These ranges are five times as large as those seen from a separate
progenitor study, where we evaluate the sensitivity of these parameters
to 32 presupernova models. Additionally, the simulations are found to be
more sensitive to a reduction in electron-capture rates than an
enhancement, and specifically to the reduction in rates for neutron-rich
nuclei near the N = 50 closed neutron shell. As measurements for
medium-heavy (A\gt 65) and neutron-rich nuclei are sparse, and because
accurate theoretical models that account for nuclear structure
considerations of individual nuclei are not readily available, rates for
these nuclei may be overestimated. If more accurate estimates confirm
this, results from this study indicate that significant changes to the
core-collapse trajectory are expected. For this reason, experimental and
theoretical efforts should focus on this region of the nuclear chart.Owen, J. E.: UV Driven Evaporation of Close-in Planets: Energy-limited, Recombination-limited, and Photon-limited Flows
http://adsabs.harvard.edu/abs/2016ApJ...816...34O
We have investigated the evaporation of close-in exoplanets irradiated
by ionizing photons. We find that the properties of the flow are
controlled by the ratio of the recombination time to the flow timescale.
When the recombination timescale is short compared to the flow
timescale, the flow is in approximate local ionization equilibrium with
a thin ionization front where the photon mean free path is short
compared to the flow scale. In this “recombination-limited”
flow the mass-loss scales roughly with the square root of the incident
flux. When the recombination time is long compared to the flow timescale
the ionization front becomes thick and encompasses the entire flow with
the mass-loss rate scaling linearly with flux. If the planet's potential
is deep, then the flow is approximately “energy-limited”
however, if the planet's potential is shallow, then we identify a new
limiting mass-loss regime, which we term “photon-limited.”
In this scenario, the mass-loss rate is purely limited by the incoming
flux of ionizing photons. We have developed a new numerical approach
that takes into account the frequency dependence of the incoming
ionizing spectrum and performed a large suite of 1D simulations to
characterize UV driven mass-loss around low-mass planets. We find that
the flow is “recombination-limited” at high fluxes but
becomes “energy-limited” at low fluxes; however, the
transition is broad occurring over several orders of magnitude in flux.
Finally, we point out that the transitions between the different flow
types do not occur at a single flux value but depend on the planet's
properties, with higher-mass planets becoming
“energy-limited” at lower fluxes.Motl, P. M.: Merger of Magnetized Binary Neutron Stars
http://adsabs.harvard.edu/abs/2016AAS...22742302M
We present simulations of the merger of binary neutron star systems
calculated with full general relativity and incorporating the global
magnetic field structure for the stars evolved with resistive
magnetohydrodynamics. We also incorporate the effects of neutrino
transport and tabular equations of state to describe the degenerate
matter. We gratefully acknowledge the support of NASA through the
Astrophysics Theory Program grant NNX13AH01G.